- [x] 1.1 Extend `saveNote` in `shared/storage.js` with an optional caret parameter (`{ caretStart, caretEnd, scrollTop }`); when provided, write those fields onto the record (both insert and update-in-place paths); when absent, preserve existing fields
- [x] 1.2 Verify old records without caret fields still load and save unchanged (no IndexedDB version bump)
- [x] 2.1 In `sidepanel/sidepanel.js`, pass current caret (`selectionStart`/`selectionEnd`) and `scrollTop` to `saveNote` in the existing autosave (`doSave`)
- [x] 2.2 Track caret-only movement via `document``selectionchange` (filtered to the editor) and editor `scroll`; debounce ~800ms into a caret-only save that calls `saveNote` without broadcasting; skip it while a content autosave is pending
- [x] 3.1 In `loadNoteForTab`, after setting `editor.value`, restore caret via `setSelectionRange` with offsets clamped to content length (default 0 for legacy records), restore `scrollTop` (in `requestAnimationFrame` if layout timing clamps it), and call `editor.focus()`
- [x] 3.2 Make `reloadFromDB` skip the `editor.value` assignment when fetched content is identical, so remote saves never move the local caret unnecessarily
- [ ] 3.3 Manually verify focus lands when the panel opens via toolbar action and via keyboard shortcut; caret restore works on panel open, tab switch, and SPA navigation
- [x] 4.1 Add `A-` and `A+` buttons to the header in `sidepanel/sidepanel.html` before the `☰` button; style them like `#open-list` in `sidepanel/sidepanel.css`
- [x] 4.2 In `sidepanel/sidepanel.js`, implement font-size state: default 16px, range 10–24px, step 1px; apply via `editor.style.fontSize`; load from `localStorage` (`side-notes:fontSize`) at init and persist on every change
- [ ] 4.3 Wire the two buttons to decrease/increase with clamping
- [ ] 4.4 Add keyboard shortcuts in the existing keydown handler: `Ctrl/Cmd+=` (and `+` variant) increase, `Ctrl/Cmd+-` decrease, `Ctrl/Cmd+0` reset to 16px, all with `preventDefault()`
- [ ] 4.5 Verify the find match scrolling (`selectMatch`) still scrolls correctly at min and max font sizes
## 5. Validation
- [ ] 5.1 Load the unpacked extension and walk every scenario in `specs/note-editor/spec.md` and `specs/notes-storage/spec.md`
- [ ] 5.2 Two-panel test: same note in two tabs — caret-only movement in A does not disturb B's caret; content edit in A still refreshes B (immediately when unfocused, deferred until blur when focused)
