feat: v4.6.0 — AI assistant, collaboration, knowledge base, and 15 more features

- AI Assistant plugin: multi-provider chat (OpenAI/Anthropic/Ollama/LM Studio),
  summarize/improve/translate commands, proofread via ai:analyze; calls
  proxied through main so API keys stay out of the renderer
- Collaboration plugin: anchor-based comments in .comments/ sidecars with
  drift detection and F8 navigation
- Local knowledge base: [[wiki-links]] with click-to-create + Backlinks panel
- Crash recovery: debounced session snapshots with restore prompt on launch
- Version history: pre-save snapshots, History panel with restore/diff/delete
- Real PDF encryption: swap pdf-lib for @cantoo/pdf-lib (probe-driven UI)
- XLSX export (native workbooks via JSZip), ODT headers/footers + page size
- Offline KaTeX (bundled CSS+fonts), local-first PlantUML rendering
- Editor: vim mode toggle, snippet Tab-expansion, zen word-goal setter,
  writing heatmap, writing-studio panels wired with rail icons
- Quick Note global scratchpad (Ctrl+Alt+Q), markdownconverter:// deep links,
  REPL first-run confirmation
- Fix: Ctrl+Shift+P collision, pandoc converter availability check, CLI
  dangling --css/--reference-doc flags, dead converter button

8 new test suites; 613 tests green; lint clean

tests/collaboration-comment-store.test.js

@@ -0,0 +1,149 @@
+/**
+ * Collaboration comment-store tests — pure logic with in-memory IO fakes,
+ * covering persistence, navigation ordering, and anchor drift detection.
+ */
+const path = require('path');
+const store = require('../src/plugins/built-in/collaboration/comment-store');
+
+/** In-memory IO fake shaped like the plugin's IPC adapters. */
+function makeIo(initial = {}) {
+  const files = new Map(Object.entries(initial));
+  return {
+    files,
+    readFile: (p) => (files.has(p) ? files.get(p) : null),
+    writeFile: (p, c) => {
+      files.set(p, c);
+    },
+    fileExists: (p) => files.has(p),
+    ensureDirectory: () => {},
+  };
+}
+
+describe('comment-store', () => {
+  const doc = path.join('/docs', 'notes.md');
+  const sidecar = path.join('/docs', '.comments', 'notes.md.json');
+
+  describe('commentsFilePathFor', () => {
+    it('places the sidecar in .comments/ next to the document', () => {
+      expect(store.commentsFilePathFor(doc, path)).toBe(sidecar);
+      expect(store.commentsFilePathFor('/a/b/c.md', path)).toBe(
+        path.join('/a/b/.comments', 'c.md.json')
+      );
+    });
+  });
+
+  describe('load/save round-trip', () => {
+    it('returns [] for documents with no sidecar yet', () => {
+      expect(store.loadComments(doc, makeIo(), path)).toEqual([]);
+    });
+
+    it('returns [] for corrupt JSON instead of throwing', () => {
+      const io = makeIo({ [sidecar]: '{oops' });
+      expect(store.loadComments(doc, io, path)).toEqual([]);
+    });
+
+    it('persists and reloads comments sorted by line', () => {
+      const io = makeIo();
+      const comments = [];
+      store.addComment(comments, { line: 12, anchorText: 'para two', text: 'expand this' });
+      store.addComment(comments, { line: 3, anchorText: 'intro', text: 'strong opener' });
+      store.saveComments(doc, comments, io, path);
+
+      const loaded = store.loadComments(doc, io, path);
+      expect(loaded.map((c) => c.line)).toEqual([3, 12]);
+      expect(loaded[0].text).toBe('strong opener');
+      expect(loaded[0].resolved).toBe(false);
+    });
+
+    it('normalizes malformed entries on load', () => {
+      const io = makeIo({
+        [sidecar]: JSON.stringify({
+          comments: [
+            { line: '7', text: 42 },
+            { line: 2, text: 'ok', author: 'ana' },
+          ],
+        }),
+      });
+      const loaded = store.loadComments(doc, io, path);
+      // '7' (string line) is dropped; the valid one survives normalization
+      expect(loaded).toHaveLength(1);
+      expect(loaded[0]).toMatchObject({ line: 2, author: 'ana' });
+    });
+  });
+
+  describe('mutators', () => {
+    it('addComment clamps lines and caps field lengths', () => {
+      const comments = [];
+      const c = store.addComment(comments, {
+        line: -5,
+        anchorText: 'x'.repeat(500),
+        text: 'y'.repeat(5000),
+      });
+      expect(comments).toHaveLength(1);
+      expect(c.line).toBe(1);
+      expect(c.anchorText.length).toBeLessThanOrEqual(200);
+      expect(c.text.length).toBeLessThanOrEqual(4000);
+      expect(c.id).toBeTruthy();
+    });
+
+    it('toggleResolved flips state and returns null for unknown ids', () => {
+      const comments = [];
+      const c = store.addComment(comments, { line: 1, text: 'hi' });
+      expect(store.toggleResolved(comments, c.id)).toBe(true);
+      expect(store.toggleResolved(comments, c.id)).toBe(false);
+      expect(store.toggleResolved(comments, 'missing')).toBeNull();
+    });
+
+    it('deleteComment reports whether anything was removed', () => {
+      const comments = [];
+      const c = store.addComment(comments, { line: 1, text: 'hi' });
+      expect(store.deleteComment(comments, c.id)).toBe(true);
+      expect(comments).toHaveLength(0);
+      expect(store.deleteComment(comments, c.id)).toBe(false);
+    });
+  });
+
+  describe('nextUnresolved (F8 navigation)', () => {
+    it('returns the first open comment below the cursor line', () => {
+      const comments = [
+        { id: 'a', line: 5, resolved: false },
+        { id: 'b', line: 20, resolved: false },
+      ];
+      expect(store.nextUnresolved(comments, 7).id).toBe('b');
+    });
+
+    it('wraps to the top when no open comments are below', () => {
+      const comments = [
+        { id: 'a', line: 5, resolved: false },
+        { id: 'b', line: 20, resolved: true },
+      ];
+      expect(store.nextUnresolved(comments, 10).id).toBe('a');
+    });
+
+    it('returns null when everything is resolved or empty', () => {
+      expect(store.nextUnresolved([{ id: 'a', line: 1, resolved: true }], 1)).toBeNull();
+      expect(store.nextUnresolved([], 1)).toBeNull();
+    });
+  });
+
+  describe('anchorStatus (drift detection)', () => {
+    const base = { line: 2, anchorText: 'original text' };
+
+    it('reports ok when the line still matches', () => {
+      expect(store.anchorStatus(base, ['first', 'original text', 'third'])).toBe('ok');
+    });
+
+    it('reports changed when the line text differs', () => {
+      expect(store.anchorStatus(base, ['first', 'edited text', 'third'])).toBe('changed');
+    });
+
+    it('reports missing when the line is beyond the document', () => {
+      expect(store.anchorStatus({ ...base, line: 99 }, ['only'])).toBe('missing');
+      expect(store.anchorStatus(base, [])).toBe('missing');
+    });
+
+    it('reports moved for comments without an anchor snippet', () => {
+      expect(store.anchorStatus({ line: 1, anchorText: '' }, ['whatever'])).toBe('moved');
+    });
+  });
+});