chore(deps): Tier A cross-ecosystem patch/minor sweep

No expected behavior changes; CI verifies. Tracked in Fable #463
under audit note #460.

Flutter (pubspec.yaml):
- flutter_secure_storage ^10.1.0 → ^10.2.0
- mocktail ^1.0.4 → ^1.0.5

Web (package.json + package-lock.json):
- @sveltejs/adapter-static ^3.0.6 → ^3.0.10
- @types/node ^25.6.0 → ^25.9.1
- autoprefixer ^10.4.20 → ^10.5.0
- postcss ^8.4.49 → ^8.5.15
- svelte-check ^4.0.5 → ^4.4.8

Tools (package.json + package-lock.json):
- sharp ^0.33.5 → ^0.34.5 (the lockfile diff is large because
  sharp ships pre-built binaries for many platform/arch combos;
  each version revs all those entries)

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tools/package.json

@@ -6,6 +6,6 @@
     "gen-og-placeholder": "node gen-og-placeholder.mjs"
   },
   "devDependencies": {
-    "sharp": "^0.33.5"
+    "sharp": "^0.34.5"
   }
 }