feat(studio): central error helpers + inline log viewer + Today CTAs

Bundles the error-UX overhaul and the inline log viewer:

  - New `FaiLog` (`~/.fai/logs/studio-errors.log`, 256 KiB rotation,
    JSON-per-line). Every operator-visible failure is appended so
    `fai admin doctor` and the new viewer can show the trail
    without the operator having to reproduce the failure.
  - New `showFaiErrorSnack` / `showFaiErrorDialog` helpers wrap
    `FaiErrorBox` in copyable surfaces; 27 ad-hoc
    `SnackBar(content: Text(e.toString()))` sites swept to use
    them (settings, doctor, audit, store, module sheet, system-AI
    editor, flow output).
  - New `FaiLogViewer` modal (`showFaiLogViewer`) renders log
    files inline with line numbers, JSON-key + `[level]` token
    colouring, Copy-all, Refresh, Open-externally. Doctor's
    daemon-paths panel grows a "View" button next to "Open" for
    every `.log` row and now also lists the Studio errors log.
  - Today carousel: CTAs now actually re-run search after a
    `filterCategory` / `runQuery` story is tapped (was only
    flipping the chip state). Fallback story list bumped to 8.
  - Editor bumped to git ref carrying 0.15.0 (type-token
    colouring + analyzer diagnostics).

Studio bumped to 0.62.0.

Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>

lib/widgets/theme_picker_grid.dart

@@ -204,6 +204,7 @@ class _Tile extends StatelessWidget {
   final List<Color> swatches;
   final bool selected;
   final bool loading;
+
   /// Adds a small tune icon at the top-right, telegraphing
   /// "this tile opens an editor instead of applying
   /// immediately". Used for the Custom tile so the operator