Bigger editor canvas, larger annotation text, plugin UI hidden in captures ...

- Fullscreen editor: toolbar and Save/Cancel now float above the canvas,
  which takes the entire window (1344x896 vs 1147x765 at 1440x900).
- Extension composer widened to 1100px, drawing area raised to 62vh.
- Text tool renders ~2.4x larger (strokeWidth * 12, min 24px); size
  slider now goes up to 20.
- Screenshots never contain the plugin's own UI: the background hides the
  overlay host around every captureVisibleTab (covers region capture,
  full-page tiles and recorder step screenshots); the region selector
  keeps it hidden for the whole stitch via a refcounted module.
- e2e saves a step screenshot for inspection; fixed its file download to
  resolve attachment id -> file id.

Co-Authored-By: Claude Code <noreply@anthropic.com>

Make the annotation editor comfortable to draw in ...

- AnnotationEditor gains a fit="contain" mode: the canvas scales to fit
  its box entirely instead of being cropped to container width.
- Report page: "Edit annotations" now opens a fullscreen editor overlay
  (toolbar + large canvas + Save/Cancel, Escape cancels) instead of the
  small inline editor.
- Extension composer: widened to 920px and the screenshot area now takes
  55vh with the canvas contain-fit, so there is actual room to draw.

Co-Authored-By: Claude Code <noreply@anthropic.com>

Annotated screenshots in lightbox; region/whole-page capture in extension ...

- Extract shared shapeDraw.ts (pen/arrow/rect/text) used by both the
  annotation editor and the viewer.
- ScreenshotViewer lightbox now renders a canvas with the screenshot plus
  annotation shapes baked in, so opening a screenshot fullscreen shows the
  drawn version instead of the raw image.
- New RegionSelector step in the extension: after picking an element, the
  page is captured pristine (before any overlay renders) and the user can
  either drag a region on the page (cropped at devicePixelRatio) or take
  the whole page via the button / Enter.
- Whole-page capture scrolls and stitches viewport tiles, hiding the
  overlay and fixed/sticky elements; per-tile captures retry with backoff
  because captureVisibleTab is throttled.
- NoteComposer receives the screenshot from the region selector instead of
  capturing on its own; e2e updated (Enter = whole page).

Co-Authored-By: Claude Code <noreply@anthropic.com>

Web panel: Vue 3 + gnexus-ui-kit, auth, projects, reports, i18n ...

- Monorepo packages: @ltt/shared (types+client), @ltt/ui (AnnotationEditor,
  ScreenshotViewer, ElementContext, EnvironmentInfo), @ltt/web (panel)
- Kit assets served at /assets in dev and build (absolute font URL workaround)
- Pages: login/register, projects, public project+report pages (token=auth),
  settings with en/ru switcher
- Annotation editor: pen/arrow/rect/text, Tokyo Night palette, undo,
  fraction coordinates, vector shapes persisted via attachment PATCH

Co-Authored-By: Claude Code <noreply@anthropic.com>