Add parser doctor, offline queue, tag inheritance, logo, MIT license

Parser doctor:
- validateContent() with error/warning severity levels
- Errors: invalid date, invalid priority, reminder without due,
  invalid reminder unit
- Warnings: time without date, past date, multiple metadata,
  typo detection with correction suggestions
- 21 new tests in ParserDoctorTest

Tag inheritance:
- extractTasks() accepts memoTags parameter
- Tasks without #tags inherit memo-level tags

Offline queue:
- PendingSyncEntity + PendingSyncDao for queued edits
- MemoRepository queues failed API calls, drains on next sync
- Sync status banner: "synced N min ago" / "offline · N pending"

UI:
- Parser doctor banner in tasks tab with inline highlighting
- Error/warning dots on task rows
- Pivot headers with absolute positioning and measured widths
- Logo in settings about section (Canvas-drawn circle variant)

Other:
- MIT license
- Logo design spec (LOGO.md)
- Concentric circle logo: pink circle, black+teal 47° annular wedge
- .gitignore updated for dev artifacts

144 tests passing.

Co-Authored-By: Claude Opus 4.6 (1M context)

Signed-off-by: Avinal Kumar <avinal.xlvii@gmail.com>

.gitignore

@@ -25,3 +25,8 @@ composeApp/schemas/
 index.html
 script.js
 styles.css
+
+# Dev artifacts
+PLAN.md
+Screenshot_*.png
+logo-*.svg