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/commands/composer-mock.md

@@ -0,0 +1,28 @@
+---
+description: Generate or revise a JSX/TSX mock for a named user flow. Mocks are high-fidelity but non-functional, reference the design system and interaction design, and pass a text feasibility audit before being committed.
+arguments:
+  - name: flow
+    description: The flow to mock (must exist in flows.md). If omitted, lists available flows.
+    required: false
+---
+
+Invoke the `composer-mocks` skill with `$ARGUMENTS`.
+
+Prerequisites the skill checks before generating:
+
+1. `docs/planning/flows.md` exists and names the flow.
+2. `docs/planning/design-system.md` exists (tokens, type, components vocabulary).
+3. `docs/planning/interaction-design.md` exists (state surfaces, motion, input, i18n, breakpoints).
+4. `docs/planning/mocks/tokens.ts` is current with `design-system.md`.
+
+If any prerequisite is missing the skill stops and points at it. The mock is
+only as good as the systems it references.
+
+After generation the skill runs a **text feasibility pass**: every visible
+string is categorized (static, computed, authored), computed strings are
+traced to source data and transformations, and any string that implies an
+unspecified feature is flagged for the user to either spec properly or remove
+from the mock.
+
+After a clean text pass, the skill optionally summons Marge (end-user) and
+Maya (a11y) for a review.