feat(composer): discovery-phase plugin from "I want an app that..." to tracker-loaded stories

Plugin pairs with Symphony — Composer's output (issues in the project's
tracker) is Symphony's input. State-aware /composer command walks the
user through 11 phases: concept, users (with workflow probing for hidden
actors), requirements/NFR/IA, design system, interaction design, flows,
mocks, architecture, stories, roadmap, load. Each phase produces a
reviewable artifact in docs/planning/ (or, for design and interaction,
a project-local skill — see below).

Architecture is intentionally LAST, after the spec is complete. Mocks
are JSX/TSX regardless of final stack and pass a "text feasibility"
audit — every visible string is categorized (static/computed/authored),
computed strings are traced to source data, and any string implying an
unspecified feature halts the commit.

Design system and interaction design are produced as PROJECT-LOCAL
SKILLS in .claude/skills/<slug>-design-system/ and
.claude/skills/<slug>-interaction-design/, not as docs in
docs/planning/. Skills auto-load via description matching whenever UI
work happens; a reference doc gets read once and drifts out of context.
The mocks skill imports tokens directly from the design-system skill
for a single source of truth across mocks and (eventually) real code.

ui-system is currently a PLACEHOLDER — captures the minimum needed for
mocks to proceed with <TBD: ...> markers as a return-pass worklist.
Full interview specification is the next pass.

Council touchpoints baked in: PM/skeptic/end-user after requirements,
end-user/a11y after mocks, full architecture council after architecture,
plus auto-additions (legal-triage on regulated data, privacy-advocate
on PII, finance-controller on money flows).

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

composer/templates/design-system/components.md

@@ -0,0 +1,52 @@
+# Component vocabulary
+
+The named components for <PROJECT NAME>. Match names from `ia.md`
+where applicable. Do not introduce new components without proposing
+them here first.
+
+This file is loaded automatically by the design-system skill — agents
+generating UI should be aware of every component in this list and
+prefer them to ad-hoc one-offs.
+
+## Primitives
+
+### Button
+- **Variants**: primary | secondary | ghost | destructive | link
+- **Sizes**: sm | md | lg
+- **States**: default | hover | active | focus | disabled | loading
+- **Anatomy**: optional leading icon · label · optional trailing icon
+- **Motion**: <TBD>
+
+### Input
+- **Variants**: text | textarea | select | checkbox | radio | toggle
+- **Sizes**: sm | md | lg
+- **States**: default | focus | error | disabled | readonly
+- **Anatomy**: label · field · helper text · error message
+- **Validation pattern**: <TBD — see interaction-design skill>
+
+### Card / Surface
+- **Variants**: <flat | bordered | elevated — pick or list>
+- **Anatomy**: <header? · body · footer?>
+
+## Project-specific components
+
+<!--
+Pulled from ia.md. One block each, with anatomy and any state-specific
+notes that should always apply when this component is rendered.
+-->
+
+### <Component name>
+
+- **Purpose**: <one line>
+- **Anatomy**: <slots / regions>
+- **States**: <list>
+- **Notes**: <anything load-bearing>
+
+## Patterns to avoid
+
+<!--
+Things that come up often and should be vetoed. Saves the agent from
+re-inventing them.
+-->
+
+- <TBD: e.g., "no nested cards", "no inline icons in body text", etc.>