Project tags, color picker, and command palette polish

[Ron537]

Adds free-form project tags so a large project list can be grouped by relationship (clients, infra, OSS, etc.), with a color picker, dynamic-fit row rendering, and a polish pass on the command palette so tags are first-class there too.

What's new

Tagging

• New tags?: string[] field on Project, persisted through the existing settings round-trip.
• Right-click a project → Tags… opens a multi-select picker that suggests existing tags from across the workspace and creates new ones inline (typing #infra and infra both normalize to the same canonical tag).
• Tag filter strip at the top of the projects sidebar — single-select, auto-hides when no project has any tag, self-heals when the active tag disappears.

Color picker

• Each tag carries a globally-shared color users can pick from an 8-swatch theme-safe palette (TAG_PALETTE). Same palette on both light and dark themes.
• The Create row in the picker shows a stable-color preview that doesn't shimmer as the user types; existing tags can be recolored from a per-row swatch strip.
• Defaults to a deterministic hash of the tag name, so first-time tags already have a consistent look.

Dynamic-fit rendering

• New InlineTagList measures pill widths via ResizeObserver against container width and shows as many tags as actually fit. Overflow surfaces as a +N chip whose tooltip lists the hidden tags — nothing is silently clipped.
• Long tag names truncate with ellipsis instead of pushing siblings off-screen.

Worktree-with-parent filtering

• Filtering by tag (or any other filter) keeps a matched parent's worktree subtree visible underneath it; matching parents are force-expanded without touching the user's persisted expand/collapse state.

Command palette (⌘P)

• Project results render with the project avatar and tag pills inline, so users can see at a glance why a result matched.
• Tag keywords are emitted both bare (infra) and prefixed (#infra) so #infra filters projects directly.
• Placeholder hints (try #tag).

Discoverability

• Status bar gets a persistent Search ⌘P button.
• Settings → Shortcuts entry for ⌘P now reads "Global search — projects, sessions, tabs, settings (try #tag)".

Tests

11 new unit tests for tag normalization, the store actions, color resolution, and dedupe — total suite now 352 passing.

Review

Ran the dual review policy (claude-opus-4.7 + gpt-5.5). All findings from both rounds addressed:

• Anchor for the tag picker is the row div (not the whole expanded wrapper)
• Stale tag filter self-heals when the active tag is removed
• #-prefixed typing in the picker still matches existing tags
• Enter on an existing tag no longer overwrites its global color
• Collapsed matched parents force-expand in filter mode
• All lint rules pass

Version

Bumped to 0.16.0 (MINOR — new user-visible features). CHANGELOG updated.