Feat v0.4.2 tags search

Tags table (ext_notes_tags), tag CRUD API, tag filtering in sidebar,
tag pills on note cards, drag-and-drop note-to-folder moves, folder
context menu replacing prompt() hack. Notes package bumped to v0.3.0.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

CHANGELOG.md

@@ -2,6 +2,45 @@
 
 All notable changes to Switchboard Core are documented here.
 
+## v0.4.2 — Tags + Search
+
+### Added
+
+- **Tags table** (`ext_notes_tags`): note_id, tag columns with indexes on
+  both for bidirectional lookup. Many-to-many relationship via join table.
+- **Tag CRUD API**: 3 new Starlark handlers — list all unique tags, get tags
+  for a note, replace tags for a note (delete-all + reinsert). Tags are
+  normalized to lowercase, trimmed, and deduplicated on save.
+- **Tags in list/get/search**: `_list_notes` batch-fetches all tags in a
+  single query and attaches a `tags` array to each note item. `_get_note`
+  includes tags. `_search_notes` now matches search terms against tags.
+- **Tag cascade delete**: Hard-deleting a note also removes its tag rows.
+- **Tag input in editor**: `TagInput` component with removable pills, text
+  input (comma or Enter to add), and autocomplete dropdown populated from
+  all existing tags.
+- **Tag pills on note cards**: `NoteCard` renders up to 3 tag pills with
+  "+N" overflow indicator for notes with many tags.
+- **Tag filter in sidebar**: `TagFilter` component displays all unique tags
+  as clickable pills. Clicking toggles client-side filtering of the note
+  list by that tag.
+- **Drag-and-drop note moves**: `NoteCard` is draggable (HTML5 drag/drop).
+  `FolderNode`, "All Notes", and "Unfiled" items are drop targets. On drop,
+  calls the existing move-note API.
+- **Folder context menu**: Replaced `prompt()` hack with a proper right-click
+  popup menu showing "Add subfolder", "Rename", and "Delete" actions. Positioned
+  at click coordinates, dismissed on outside click.
+- **Updated stats**: `/stats` response now includes `tags` count (unique).
+
+### Data model
+
+| Table | Columns |
+|-------|---------|
+| `ext_notes_tags` | note_id, tag |
+
+### Notes package version
+
+Bumped from 0.2.0 → 0.3.0. 15 API routes (12 existing + 3 new).
+
 ## v0.4.1 — Folders + Navigation Tree
 
 ### Added