fix: wire catalog add buttons, fix Trans bold rendering, lint cleanup

- CatalogSearchOverlay: replace handleAddStub with real openAddToCollection/openAddToThread routing based on catalogSearchMode
- ConfirmDialog + __root.tsx: swap t() for Trans component on deleteItemMessage, deleteCandidateMessage, pickWinnerMessage — fixes <bold> rendering as literal text
- Biome format pass: fix 23 lint/format errors across scripts, services, tests
- Planning: mark all UAT and verification gaps resolved for phases 07, 11, 16, 20, 21, 22, 24, 32, 34; close debug sessions

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.planning/todos/pending/2026-04-19-use-category-picker-in-new-thread-modal.md

@@ -0,0 +1,15 @@
+---
+created: 2026-04-19T00:00:00.000Z
+title: Use CategoryPicker in new thread creation flow (AddToThreadModal)
+area: ui
+files:
+  - src/client/components/AddToThreadModal.tsx
+---
+
+## Problem
+
+When creating a new thread from the catalog search overlay (AddToThreadModal "New Thread" mode), the category field uses a plain `<select>` instead of the standard `CategoryPicker` component. This is inconsistent with other flows in the app (e.g., ManualEntryForm, CreateThreadModal) that use CategoryPicker with icons, search, and inline create.
+
+## Desired Behavior
+
+Replace the plain category `<select>` in AddToThreadModal's create-thread mode with `CategoryPicker` to match the standard pattern.