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/data/today_story_loader.dart

@@ -20,7 +20,19 @@ import 'package:yaml/yaml.dart';
 /// closed and ABI-stable — adding a new variant without bumping
 /// the schema would let an old Studio render an unknown action
 /// as a no-op button.
-enum TodayCta { none, openSettings }
+///
+/// `filterCategory` and `runQuery` both consume the optional
+/// [TodayStoryData.ctaPayload] — a wire-string the Store page
+/// dispatches into its filter / search box. Keeping the action
+/// surface inside the Store means a hero story can teach about a
+/// section without forcing a page-route change.
+enum TodayCta {
+  none,
+  openSettings,
+  filterCategory,
+  runQuery,
+  showSuggestedSources,
+}
 
 /// Bilingual story rendered by the Today-Hero card. Either
 /// loaded from disk or supplied as a const fallback.
@@ -37,6 +49,11 @@ class TodayStoryData {
   final IconData icon;
   final TodayCta cta;
 
+  /// Wire payload used by [TodayCta.filterCategory] (category id
+  /// to apply to the Store grid) and [TodayCta.runQuery] (free-text
+  /// to drop into the search box). Empty for other variants.
+  final String ctaPayload;
+
   const TodayStoryData({
     required this.badgeEn,
     required this.badgeDe,
@@ -48,6 +65,7 @@ class TodayStoryData {
     required this.ctaLabelDe,
     required this.icon,
     required this.cta,
+    this.ctaPayload = '',
   });
 }
 
@@ -130,6 +148,7 @@ class TodayStoryLoader {
       ctaLabelDe: s('cta_label_de'),
       icon: icon,
       cta: cta,
+      ctaPayload: s('cta_payload'),
     );
   }
 
@@ -150,6 +169,12 @@ class TodayStoryLoader {
         return TodayCta.none;
       case 'openSettings':
         return TodayCta.openSettings;
+      case 'filterCategory':
+        return TodayCta.filterCategory;
+      case 'runQuery':
+        return TodayCta.runQuery;
+      case 'showSuggestedSources':
+        return TodayCta.showSuggestedSources;
       default:
         return null;
     }