v0.5.1

Desktop tag UI layer on top of the v0.5.0 tag backend.

Added

• Tauri tag commands (perima-desktop): list_tags, attach_tag,
  detach_tag, list_files_with_tags. Two-query merge (metadata +
  tags_for_hashes) with a WHY comment documenting the WAL race.
• TagPayload + FileWithTagsPayload wire types in payloads.rs;
  FileWithTagsPayload composes (not extends) FileWithMetadataPayload.
• TS Tag / FileWithTags types + api.ts wrappers (listTags,
  attachTag, detachTag, listFilesWithTags) following the existing
  fromInvoke / neverthrow pattern.
• TagChip component — colored pill with optional remove button.
  Color index computed via byte-sum mod 12 (blake3 not available in TS
  bundle; intentional deviation from spec; WHY comment explains).
• TagSidebar component — "All" + per-tag rows with attachment counts
  and aria-pressed accessibility. totalCount prop shows unfiltered
  file count next to "All". Active-state count badge uses text-blue-200
  for legibility on the blue background.
• FileTable / FileGrid tag rendering — up to 3 TagChip instances
  per row/tile with +N overflow badge.
• App.tsx client-side tag filter — selectedTagId: string | null
  state; <TagSidebar> shown when tags list is non-empty; visibleFiles
  filters files by tag id. WHY comments explain single-select deferral
  and 100-row cap effect on displayed counts.