feat: grow memory limits, add icon/actor libraries, overhaul LSP diagnostics

Compiler and VM
- make every memory map limit dynamic and adjustable at both build time and
  runtime, including compiler tables, stacks, and every execution region
- reserve and grow tables, operand and return stacks, frame segments, and
  image-building output without relocating live code or globals
- rename i/o and string helpers consistently (puts -> put_s, putn -> put_n,
  scat -> cat_s) across compiler, runtime, examples, tests, and docs
- recast and consume values assigned to globals from inside functions
- allow fixed and const together, add typed closure returns (fn:t(...)),
  multi-include syntax (include rt, run, core;), and recurse type inference
- never infer string literals as word, anywhere, as argument, variable, or
  return type
- draft docs/BORROW.md: a borrow checker less intrusive than Rust's but more
  intelligent

LSP and editor integration
- require explicit includes and give every toolchain area its own namespace
  (rt, lsp, run, core)
- hover for built-in types, inferred types, values known at hover time, array
  and pointer lifetime/size, library names in include statements, and inferred
  lifetimes with explanations
- honor /* */ comments as documentation for variables and arguments, and stop
  misattributing section headers or trailing comments as variable hints
- stream diagnostics and cancel stale requests on change
- jump to definition and references, including cross-file
- quick fixes with automatic library import, and namespace completion

Hints and diagnostics
- render hints as blue squigglies by default, with hints on/small/off per file
- suppress magic-number hints via a preceding /* */ comment, and say so
- warn on unused arguments; allow multiple _ discards in parameters, pattern
  matching, and tagged enums, warning if a _ is actually used
- rewrite hint and comment prose in professional compiler-doc register

Libraries
- add icon.zc: run-time self-modification, find/replace syntax, type and block
  edits, and step-through inspection of locals and globals
- add actor.zc: async actors with Actor<I,O>, implicit this, spawn/recv/send,
  injected into the compiler machinery at include time rather than built in

Tooling and docs
- reorganize sources, tests, and designs into subdirectories
- unify windows entry points in tinyvm.bat and add a matching tinyvm.sh
- add --help across the toolchain
- polish the learning guide, stdlib docs, and design notes

Tests
- add accept, reject, and regression coverage across the compiler, LSP,
- runtime, icon, actors, threads, formatting, and the toolchain contracts,
  plus fuzzers and property tests

6 files changed, 167 insertions, 3 deletions

diff --git a/editors/vscode/client/codeactions.js b/editors/vscode/client/codeactions.js
new file mode 100644
index 0000000..dd79b3f
--- /dev/null
+++ b/editors/vscode/client/codeactions.js
@@ -0,0 +1,27 @@
+// convert protocol edits into editor actions while rejecting stale versions.
+function convertCodeActions(vscode, results, document, expectedVersion = document.version) {
+    return (Array.isArray(results) ? results : []).flatMap(result => {
+        if (!result.edit) return [];
+        const changes = result.edit.documentChanges || Object.entries(result.edit.changes || {}).map(([uri, edits]) => ({ textDocument: { uri }, edits }));
+        if (changes.some(change => change.textDocument?.uri === document.uri.toString() && change.textDocument.version != null && change.textDocument.version !== expectedVersion)) return [];
+        const edit = new vscode.WorkspaceEdit();
+        let count = 0;
+        for (const change of changes) {
+            if (!change.textDocument || !Array.isArray(change.edits)) continue;
+            const uri = vscode.Uri.parse(change.textDocument.uri);
+            for (const replacement of change.edits) {
+                const range = replacement.range;
+                if (!range || typeof replacement.newText !== 'string') continue;
+                edit.replace(uri, new vscode.Range(range.start.line, range.start.character, range.end.line, range.end.character), replacement.newText);
+                count++;
+            }
+        }
+        if (!count) return [];
+        const action = new vscode.CodeAction(result.title, vscode.CodeActionKind.QuickFix);
+        action.edit = edit;
+        action.isPreferred = !!result.isPreferred;
+        return [action];
+    });
+}
+
+module.exports = { convertCodeActions };
diff --git a/editors/vscode/client/diagcache.js b/editors/vscode/client/diagcache.js
index 6e77207..2e1758a 100644
--- a/editors/vscode/client/diagcache.js
+++ b/editors/vscode/client/diagcache.js
@@ -42,6 +42,7 @@ function includeNames(text) {
     while ((m = tokens.exec(text)) !== null) {
         const token = m[0];
         if (token.startsWith('//') || token.startsWith('/*')) continue;
+        // include std; names the library that is part of the compiler: there is no file to read
         if (include && token.startsWith('"')) {
             names.push(token.slice(1, -1).replace(/\\([\\"nrt0])/g, (_, c) => ({ n: '\n', r: '\r', t: '\t', 0: '\0' })[c] || c));
         }
@@ -80,13 +81,20 @@ function sourceTree(text, docPath, workspace) {
 // the key for a document and the files it reads. key is null when the tree is
 // too large to cover, and then nothing is cached. deps lists every file the
 // tree names (existing or not), so a change to any of them can be noticed.
+// texts maps each file that exists to its text, which a server with no files
+// of its own is sent before it checks the document.
 function diagKey(stamp, text, docPath, workspace) {
     const tree = sourceTree(text, docPath, workspace);
     const deps = [...tree.files.keys()].sort();
-    if (!tree.complete) return { key: null, deps };
+    const texts = new Map();
+    for (const [p, hash] of tree.files) {
+        if (hash === 'missing') continue;
+        try { texts.set(p, fs.readFileSync(p, 'utf8')); } catch (e) { /* gone since it was hashed */ }
+    }
+    if (!tree.complete) return { key: null, deps, texts };
     const parts = [stamp, docPath, sha256(text)];
     for (const p of deps) parts.push(p + '=' + tree.files.get(p));
-    return { key: sha256(parts.join('\n')), deps };
+    return { key: sha256(parts.join('\n')), deps, texts };
 }
 
 // the cache itself: key -> diagnostics, least recently used first. saved is
diff --git a/editors/vscode/client/extension.js b/editors/vscode/client/extension.js
index c51b12e..3846eca 100644
--- a/editors/vscode/client/extension.js
+++ b/editors/vscode/client/extension.js
@@ -13,10 +13,12 @@ const vscode = require('vscode');
 const cp = require('child_process');
 const path = require('path');
 const fs = require('fs');
+const { convertCodeActions } = require('./codeactions');
 const { vmProcess } = require('./vmproc');
 const { wasmProcess } = require('./wasmproc');
 const { DiagCache, diagKey, fileStamp, sha256 } = require('./diagcache');
 const { hoverContents } = require('./hover');
+const { createSourceProvider } = require('./sourceprovider');
 
 const CHANNEL = 'ZC Language Server';
 const SLOW_MS = 2000;		// a request that takes longer than this is logged as slow
@@ -40,6 +42,8 @@ let store = null;			// the extension's globalState, where the cache is saved
 let cache = new DiagCache(null);
 let serverStamp = 'none';		// identifies the server build; it is part of every key
 const docKeys = new Map();		// uri -> key of the document as it is now (null: not cacheable)
+const docFiles = new Map();		// uri -> the texts of the files the document includes, sent to the server before it checks the document
+const sentFiles = new Map();	// path -> the text the server was last sent for it
 const docDeps = new Map();		// uri -> the files the document reads, for checking it again when one changes
 const serverKeys = new Map();		// uri -> key of the text the server holds
 const sentKeys = new Map();		// uri -> keys sent to the server whose diagnostics have not come back
@@ -190,6 +194,7 @@ function keyOf(doc) {
     const r = diagKey(serverStamp, doc.getText(), doc.uri.fsPath, workspaceDir());
     docKeys.set(uri, r.key);
     docDeps.set(uri, r.deps);
+    docFiles.set(uri, r.texts);
     return r.key;
 }
 
@@ -238,6 +243,17 @@ function showCached(doc) {
     return true;
 }
 
+// the server of this extension has no files of its own: it is sent the text of every file a document
+// includes, keyed by its full path, and looks an include up there. only what changed is sent again.
+function sendIncludes(uri) {
+    const texts = docFiles.get(uri);
+    if (!texts) return;
+    for (const [p, text] of texts) {
+        if (sentFiles.get(p) === text) continue;
+        sentFiles.set(p, text);
+        send({ jsonrpc: '2.0', method: 'zc/file', params: { path: p.split(path.sep).join('/'), text } });
+    }
+}
 // sends doc's text to the server: didOpen the first time, didChange after that
 function sendDoc(doc, key) {
     if (!proc || !proc.stdin.writable || !ready) return false;
@@ -248,6 +264,7 @@ function sendDoc(doc, key) {
     q.push({ key, version });
     sentKeys.set(uri, q);
     serverKeys.set(uri, key);
+    sendIncludes(uri);
     if (!opened.has(uri)) {
         opened.add(uri);
         send({ jsonrpc: '2.0', method: 'textDocument/didOpen', params: { textDocument: { uri, languageId: 'zc', version, text: doc.getText() } } });
@@ -346,6 +363,7 @@ function startServer() {
     opened.clear();
     serverKeys.clear();
     sentKeys.clear();
+    sentFiles.clear();
     docVersions.clear();
     serverStamp = serverStampFor(bin);
     const t0 = Date.now();
@@ -398,7 +416,7 @@ function startServer() {
         }
     });
     watchInit(gen, !!bin);
-    request('initialize', { processId: process.pid, capabilities: {} }).then(res => {
+    request('initialize', { processId: process.pid, rootUri: workspaceDir() ? vscode.Uri.file(workspaceDir()).toString() : null, capabilities: {} }).then(res => {
         if (gen !== generation || stopping || !proc) return;
         if (initTimer) { clearTimeout(initTimer); initTimer = null; }
         const caps = res && res.capabilities ? Object.keys(res.capabilities) : [];
@@ -527,6 +545,94 @@ function activate(context) {
         }
     };
     context.subscriptions.push(vscode.languages.registerHoverProvider({ language: 'zc' }, hover));
+
+    // the sources the server carries (the runtime, compiler, standard library and icon module): shown read only at tinyvm:/NAME.zc
+    // when go to definition lands on a built-in. the text comes from the server, so it is the code the editor's checks run on
+    context.subscriptions.push(vscode.workspace.registerTextDocumentContentProvider('tinyvm', createSourceProvider(request, () => ready)));
+
+    // completions refresh as the prefix changes; deprecated lifetime entries stay visible at the end.
+    context.subscriptions.push(vscode.languages.registerCompletionItemProvider({ language: 'zc' }, {
+        async provideCompletionItems(doc, position, token) {
+            if (!isZc(doc) || !ready || token.isCancellationRequested) return null;
+            ensureServer(doc);
+            const version = doc.version;
+            try {
+                const res = await request('textDocument/completion', { textDocument: { uri: doc.uri.toString() }, position: { line: position.line, character: position.character } });
+                if (!res || token.isCancellationRequested || doc.version !== version) return null;
+                const items = (res.items || []).map(c => {
+                    const item = new vscode.CompletionItem(c.label, c.kind ? c.kind - 1 : vscode.CompletionItemKind.Variable);
+                    item.detail = c.detail;
+                    item.sortText = c.sortText;
+                    item.filterText = c.filterText;
+                    if (c.tags && c.tags.includes(1)) item.tags = [vscode.CompletionItemTag.Deprecated];
+                    if (c.documentation) {
+                        item.documentation = new vscode.MarkdownString(c.documentation.value || c.documentation);
+                        item.documentation.isTrusted = false;
+                    }
+                    if (c.textEdit) {
+                        const r = c.textEdit.range;
+                        item.range = new vscode.Range(r.start.line, r.start.character, r.end.line, r.end.character);
+                        item.insertText = c.textEdit.newText;
+                    }
+                    return item;
+                });
+                return new vscode.CompletionList(items, !!res.isIncomplete);
+            } catch (err) { return null; }
+        }
+    }, '.', '>'));
+
+    // compiler-backed import fixes use the same document version as their diagnostics.
+    if (vscode.languages.registerCodeActionsProvider) context.subscriptions.push(vscode.languages.registerCodeActionsProvider({ language: 'zc' }, {
+        async provideCodeActions(doc, range, actionContext, token) {
+            if (!isZc(doc) || !ready || token.isCancellationRequested) return [];
+            ensureServer(doc);
+            const version = doc.version;
+            const serverVersion = docVersions.get(doc.uri.toString());
+            try {
+                const results = await request('textDocument/codeAction', {
+                    textDocument: { uri: doc.uri.toString() },
+                    range: { start: { line: range.start.line, character: range.start.character }, end: { line: range.end.line, character: range.end.character } },
+                    context: { diagnostics: [] }
+                });
+                if (token.isCancellationRequested || doc.version !== version || docVersions.get(doc.uri.toString()) !== serverVersion) return [];
+                return convertCodeActions(vscode, results, doc, serverVersion);
+            } catch (err) { return []; }
+        }
+    }, { providedCodeActionKinds: [vscode.CodeActionKind.QuickFix] }));
+
+    // go to definition and find references: the compiler's own records, including names from included files
+    const locations = (res) => (Array.isArray(res) ? res : []).map(l => new vscode.Location(vscode.Uri.parse(l.uri),
+        new vscode.Range(l.range.start.line, l.range.start.character, l.range.end.line, l.range.end.character)));
+    context.subscriptions.push(vscode.languages.registerDefinitionProvider({ language: 'zc' }, {
+        async provideDefinition(doc, position) {
+            if (!isZc(doc) || !ready) return null;
+            ensureServer(doc);
+            try {
+                return locations(await request('textDocument/definition', { textDocument: { uri: doc.uri.toString() }, position: { line: position.line, character: position.character } }));
+            } catch (err) { return null; }
+        }
+    }));
+    // formatting: the server's pretty-printer, with the editor's tab settings (a .zcformat file overrides them)
+    context.subscriptions.push(vscode.languages.registerDocumentFormattingEditProvider({ language: 'zc' }, {
+        async provideDocumentFormattingEdits(doc, options) {
+            if (!isZc(doc) || !ready) return [];
+            ensureServer(doc);
+            try {
+                const res = await request('textDocument/formatting', { textDocument: { uri: doc.uri.toString() }, options: { tabSize: options.tabSize, insertSpaces: options.insertSpaces } });
+                return (Array.isArray(res) ? res : []).map(e => vscode.TextEdit.replace(
+                    new vscode.Range(e.range.start.line, e.range.start.character, e.range.end.line, e.range.end.character), e.newText));
+            } catch (err) { return []; }
+        }
+    }));
+    context.subscriptions.push(vscode.languages.registerReferenceProvider({ language: 'zc' }, {
+        async provideReferences(doc, position, refContext) {
+            if (!isZc(doc) || !ready) return null;
+            ensureServer(doc);
+            try {
+                return locations(await request('textDocument/references', { textDocument: { uri: doc.uri.toString() }, position: { line: position.line, character: position.character }, context: { includeDeclaration: !!refContext.includeDeclaration } }));
+            } catch (err) { return null; }
+        }
+    }));
 }
 
 function deactivate() {
diff --git a/editors/vscode/client/sourceprovider.js b/editors/vscode/client/sourceprovider.js
new file mode 100644
index 0000000..d03d746
--- /dev/null
+++ b/editors/vscode/client/sourceprovider.js
@@ -0,0 +1,17 @@
+// serves source documents carried by the language server at tinyvm:/NAME.zc.
+function createSourceProvider(request, isReady, delay = ms => new Promise(resolve => setTimeout(resolve, ms))) {
+    return {
+        async provideTextDocumentContent(uri) {
+            for (let waited = 0; !isReady() && waited < 10000; waited += 100) await delay(100);
+            if (!isReady()) return '// the language server is not running\n';
+            try {
+                const result = await request('zc/source', { path: uri.path });
+                return typeof result === 'string' ? result : '// no such built-in source\n';
+            } catch (error) {
+                return '// the language server could not give this source\n';
+            }
+        }
+    };
+}
+
+module.exports = { createSourceProvider };
diff --git a/editors/vscode/client/vmproc.js b/editors/vscode/client/vmproc.js
index d4806e4..8ce8c52 100644
--- a/editors/vscode/client/vmproc.js
+++ b/editors/vscode/client/vmproc.js
@@ -51,6 +51,9 @@ function vmProcess(dir, opts = {}) {
             dead = true;
             log(status === 0 ? 'message' : 'problem', 'the vm halted with status ' + status + ' after ' + steps + ' steps, ' + bytesIn + ' bytes in, ' + bytesOut + ' out');
             proc.emit('exit', status);
+        } else if (status === 3 && vm.polling) {
+            // the server asked whether input is waiting: let the event loop deliver it, then go on
+            setImmediate(() => { if (!dead && vm.polling) after(vm.resume()); });
         }
     };
 
diff --git a/editors/vscode/client/wasmproc.js b/editors/vscode/client/wasmproc.js
index 0aa674a..e8250bc 100644
--- a/editors/vscode/client/wasmproc.js
+++ b/editors/vscode/client/wasmproc.js
@@ -58,6 +58,9 @@ function wasmProcess(file, opts = {}) {
             dead = true;
             log(status === 0 ? 'message' : 'problem', 'the server halted with status ' + status + ' after ' + steps + ' steps, ' + bytesIn + ' bytes in, ' + bytesOut + ' out');
             proc.emit('exit', status);
+        } else if (status === 3 && x.wasm_polling && x.wasm_polling()) {
+            // the server asked whether input is waiting: let the event loop deliver it, then go on
+            setImmediate(() => { if (!dead && x.wasm_polling && x.wasm_polling()) after(x.wasm_resume()); });
         }
     };