chore: bump version to 0.2.10

fix(editor): table mark shortcuts, plain-text copy, code-block copy b…

…utton

- Keymap now dispatches in the capture phase and stops propagation on a
  match, so a registered chord (Cmd+B/I, lists, …) no longer also reaches
  ProseMirror's built-in shortcut. The double dispatch toggled marks twice
  in rendered contexts (table cells), netting a no-op — it only "worked" in
  hybrid source blocks where PM's mark command is itself a no-op.
- Disable tiptap-markdown transformCopiedText: copying now yields plain
  text instead of Markdown syntax, and a table selection no longer emits
  the serializer's <table><tr><td> HTML fallback.
- Add a copy button to the left of the code-block language dropdown; the
  picker now also surfaces on hover (plain and mermaid blocks), with a
  brief checkmark confirmation on copy.

perf(editor): keep per-keystroke work proportional to the edit, not d…

…oc size

Typing into large markdown files lagged because several hot-path operations
re-ran over the whole document on every keystroke. Make them incremental:

- SourceBlock decorations: carry the prior DecorationSet forward (remapped
  through the transaction) and re-tokenize only the blocks the edit or the
  active-block transition touched, instead of re-tokenizing every block.
- Dirty-flag check: trust the undo-depth signal on the keystroke path and run
  the authoritative full-doc markdown comparison on a debounced reconcile,
  instead of serializing the whole doc every keystroke. setModified is now
  idempotent to avoid redundant notifies.
- Status-bar word/char/line/token counts: debounced (were serializing the doc
  and scanning the string synchronously per keystroke).
- Table-of-contents: debounced (collectHeadings ran querySelectorAll over the
  whole editor DOM + a layout read per heading every keystroke).
- getMarkdown(): memoize on the ProseMirror doc identity so callers in one
  update share a single serialization.

fix: render local images and toolbar inserts

fix(windows): include file association icon asset

feat(onboarding): bundle read-only Examples, shown on first run & Hel…

…p → Examples

Ship a short tour of the editor inside the binary. On a fresh install (no
preferences file) the bundled docs open as the first window; any time
later they're reachable from Help → Examples. They open as read-only tabs
in numbered filename order.

- Content: frontend/src/examples/NN-*.md, inlined at build via
  import.meta.glob (raw, eager) — no Go service. loadExamples() sorts by
  name and titles each tab from its first H1.
- Read-only tabs (new): Tab.readOnly + displayName; editor.setEditable
  (false) plus a ReadOnlyGuard filterTransaction that blocks doc edits but
  allows the tagged mode-switch conversions, so view-mode toggling still
  works. Source view (CodeMirror) goes read-only too; save + bubble menu
  gated; status bar shows "<title> · Read-only".
- Launch: ?examples=1 → openExamples(); spawnExamplesWindow() from a new
  Help → Examples menu item; first-run routing via PreferencesService.
  FirstRun() in startupSpawn.

feat(explorer): make the whole root-name cluster the dropdown hit area

Clicking the folder name (not just the chevron) now opens the recent/pinned
roots dropdown — same whole-area hit target as the find/replace mode toggle.
The chevron's clicks bubble to the cluster handler (no double-toggle), the
click-away guard tracks the cluster, and the cluster is cursor:pointer +
non-selectable so it reads as a control.

v0.2.3

- fix: Windows no longer hangs on launch (entry top-level-await deadlocked
  WebView2/V8 inside an import cycle); toolbar, explorer and editor now mount.
- fix: Windows/Linux get a Help menu with About + Check for Updates (no longer
  orphaned in File; About shows the version).
- boot: self-diagnosing boot-failure banner + breadcrumbs as a regression guard.
- mermaid: diagrams themed to the app design tokens.

ci(release): stop OSS pipeline from publishing on tag push

md-pro's pipeline publishes the official (pro) release to this repo and, in
doing so, creates the version tag here via a PAT — which re-triggered THIS
OSS workflow and overwrote the pro assets with an OSS build (v0.2.2 shipped
OSS as a result). Drop the `push: tags` trigger; keep workflow_dispatch for
on-demand OSS build validation (it doesn't publish — the release job is
tag-gated).

ci(release): collect Windows installer from bin/ + rc-safe version re…

…source

NSIS writes the installer to bin/ (project.nsi OutFile), not build/windows/nsis,
so the collect glob missed it and only the raw .exe was published. Also strip
any prerelease suffix when stamping the OS version resource (build-assets), so a
-rc/-beta tag won't break the Windows VERSIONINFO/NSIS build. (Mirrors the fixes
in the md-pro pro release pipeline.)