Any seat can be AI-staffed: engineer/designer/analyst atoms + role-aware seat suggestions

The core product thesis made tangible beyond PO/QA:
- Four new golden-tested skill atoms in skills/: code-implementation + bug-diagnosis
  (engineer — output is a reviewable patch/diagnosis artifact; Git write-back stays Phase 2),
  ui-design-spec (designer), requirements-analysis (analyst, also tagged product-owner).
  The catalogue now spans five roles with eight atoms.
- Seat configurator: SuggestedSkills — maps the seat's free-text role name to skill role
  tags and offers the matching set one click ("Use set"). Any role name → staffed with AI.
- AnyRoleSeatTests: an "Backend Engineer" seat (Edison, gated) runs the same pipeline —
  skills assemble, implement-code/Draft parsed, proposal held in the review inbox like any
  governed action. SkillSyncTests updated for the larger catalogue.

Verified: IntegrationTests 44/44, client build green.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

skills/ui-design-spec/SKILL.md

@@ -0,0 +1,38 @@
+---
+id: ui-design-spec
+name: UI Design Spec
+version: 1.0.0
+summary: Turn a feature into a concrete screen spec — layout, components, states, and flows.
+roles: [designer]
+inputs: A feature or story, plus the product's design language notes if attached.
+outputs: A screen-by-screen spec — layout, components, interaction states, and the user flow.
+actions:
+  - name: write-design-spec
+    risk: draft
+    description: Produce the design spec as a draft artifact on the task (held for review).
+tools: []
+context: [house-style, design-system]
+visibility: public
+min_tier: free
+golden_tests:
+  - input: "Feature: users need a way to log out from anywhere in the app."
+    expected: |
+      Placement: avatar menu, top-right header, last item "Log out" with icon.
+      States: confirm none (instant), loading spinner on click, redirect to /login.
+      Flow: any page → avatar menu → Log out → /login with a "signed out" toast.
+---
+
+# UI Design Spec
+
+You are a product designer. Specify the screen(s) so a developer can build them without
+guessing.
+
+For each screen or surface:
+
+- **Layout** — regions and hierarchy (what's where, and why).
+- **Components** — name them in the product's design system terms where possible.
+- **States** — empty, loading, error, success, and permission-restricted variants.
+- **Flow** — entry points, the happy path, and exits.
+- **Copy** — exact labels for buttons, titles, and empty states.
+
+Stay inside the existing design language; flag any new pattern you introduce and justify it.