Release v0.4.0: UX pipeline, game-dev improvements

## New Skills (9)
- /quick-design: lightweight spec path for small changes (bypasses full GDD pipeline)
- /story-readiness: validates stories are implementation-ready before pickup
- /story-done: end-of-story completion review (criteria verification, deviation check, status update)
- /sprint-status: fast 30-line sprint snapshot, read-only
- /ux-design: guided section-by-section UX spec authoring (screen/flow/HUD/patterns)
- /ux-review: UX spec validation with APPROVED/NEEDS REVISION/MAJOR REVISION verdict
- /architecture-review, /create-architecture, /create-control-manifest,
  /create-epics-stories, /propagate-design-change, /review-all-gdds (pipeline completion)

## New Templates (7)
- player-journey.md: 6-phase emotional arc, critical moments, retention hooks
- difficulty-curve.md: difficulty axes, onboarding ramp, cross-system interactions
- ux-spec.md: per-screen UX spec with states, interaction map, data requirements, events
- hud-design.md: whole-game HUD with philosophy, info architecture, element specs
- accessibility-requirements.md: project-wide accessibility tier commitment and audit
- interaction-pattern-library.md: 26 standard + game-specific patterns with full state specs
- architecture-traceability.md: GDD requirements to ADR coverage matrix

## Updated Skills & Templates
- gate-check: Vertical Slice hard gate, playtesting strengthened, UX artifacts required
- team-ui: full UX pipeline integration (/ux-design + /ux-review + accessibility-specialist)
- game-design-document: Game Feel section (input latency, animation frames, impact moments)
- implementation-agent-protocol: /story-done as explicit final step of every story
- architecture-decision, design-system: pipeline completion updates

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/skills/gate-check/SKILL.md

@@ -58,12 +58,16 @@ The project progresses through these stages:
 
 **Required Artifacts:**
 - [ ] Systems index exists at `design/gdd/systems-index.md` with at least MVP systems enumerated
-- [ ] At least 1 GDD in `design/gdd/` (beyond game-concept.md and systems-index.md)
+- [ ] All MVP-tier GDDs exist in `design/gdd/` and individually pass `/design-review`
+- [ ] A cross-GDD review report exists in `design/gdd/` (from `/review-all-gdds`)
 
 **Quality Checks:**
-- [ ] GDD(s) pass design review (8 required sections present)
-- [ ] System dependencies are mapped in the systems index
+- [ ] All MVP GDDs pass individual design review (8 required sections, no MAJOR REVISION NEEDED verdict)
+- [ ] `/review-all-gdds` verdict is not FAIL (cross-GDD consistency and design theory checks pass)
+- [ ] All cross-GDD consistency issues flagged by `/review-all-gdds` are resolved or explicitly accepted
+- [ ] System dependencies are mapped in the systems index and are bidirectionally consistent
 - [ ] MVP priority tier is defined
+- [ ] No stale GDD references flagged (older GDDs updated to reflect decisions made in later GDDs)
 
 ---
 
@@ -72,12 +76,32 @@ The project progresses through these stages:
 **Required Artifacts:**
 - [ ] Engine chosen (CLAUDE.md Technology Stack is not `[CHOOSE]`)
 - [ ] Technical preferences configured (`.claude/docs/technical-preferences.md` populated)
-- [ ] At least 1 Architecture Decision Record in `docs/architecture/`
-- [ ] Engine reference docs exist in `docs/engine-reference/`
+- [ ] At least 3 Architecture Decision Records in `docs/architecture/` covering
+      Foundation-layer systems (scene management, event architecture, save/load)
+- [ ] Engine reference docs exist in `docs/engine-reference/[engine]/`
+- [ ] Master architecture document exists at `docs/architecture/architecture.md`
+- [ ] Architecture traceability index exists at `docs/architecture/architecture-traceability.md`
+- [ ] `/architecture-review` has been run (a review report file exists in `docs/architecture/`)
+- [ ] `design/accessibility-requirements.md` exists with accessibility tier committed
+- [ ] `design/ux/interaction-patterns.md` exists (pattern library initialized, even if minimal)
 
 **Quality Checks:**
 - [ ] Architecture decisions cover core systems (rendering, input, state management)
 - [ ] Technical preferences have naming conventions and performance budgets set
+- [ ] Accessibility tier is defined and documented (even "Basic" is acceptable — undefined is not)
+- [ ] At least one screen's UX spec started (often the main menu or core HUD is designed during Technical Setup)
+- [ ] All ADRs have an **Engine Compatibility section** with engine version stamped
+- [ ] All ADRs have a **GDD Requirements Addressed section** with explicit GDD linkage
+- [ ] No ADR references APIs listed in `docs/engine-reference/[engine]/deprecated-apis.md`
+- [ ] All HIGH RISK engine domains (per VERSION.md) have been explicitly addressed
+      in the architecture document or flagged as open questions
+- [ ] Architecture traceability matrix has **zero Foundation layer gaps**
+      (all Foundation requirements must have ADR coverage before Pre-Production)
+
+**Engine Validation** (read `docs/engine-reference/[engine]/VERSION.md` first):
+- [ ] ADRs that touch post-cutoff engine APIs are flagged with Knowledge Risk: HIGH/MEDIUM
+- [ ] `/architecture-review` engine audit shows no deprecated API usage
+- [ ] All ADRs agree on the same engine version (no stale version references)
 
 ---
 
@@ -87,11 +111,44 @@ The project progresses through these stages:
 - [ ] At least 1 prototype in `prototypes/` with a README
 - [ ] First sprint plan exists in `production/sprints/`
 - [ ] All MVP-tier GDDs from systems index are complete
+- [ ] Master architecture document exists at `docs/architecture/architecture.md`
+- [ ] At least 3 ADRs covering Foundation-layer decisions exist in `docs/architecture/`
+- [ ] Control manifest exists at `docs/architecture/control-manifest.md`
+      (generated by `/create-control-manifest` from Accepted ADRs)
+- [ ] Epics and stories defined in `production/epics/` with at least Foundation
+      and Core layer epics present (use `/create-epics-stories layer: foundation`
+      and `/create-epics-stories layer: core` to create them)
+- [ ] Vertical Slice build exists and is playable (not just scope-defined)
+- [ ] Vertical Slice has been playtested with at least 3 sessions (internal OK)
+- [ ] Vertical Slice playtest report exists at `production/playtests/` or equivalent
+- [ ] UX specs exist for key screens: main menu, core gameplay HUD (at `design/ux/`), pause menu
+- [ ] HUD design document exists at `design/ux/hud.md` (if game has in-game HUD)
+- [ ] All key screen UX specs have passed `/ux-review` (verdict APPROVED or NEEDS REVISION accepted)
 
 **Quality Checks:**
-- [ ] Prototype validates the core loop hypothesis
-- [ ] Sprint plan references real work items from GDDs
-- [ ] Vertical slice scope is defined
+- [ ] **Core loop fun is validated** — playtest data confirms the central mechanic is enjoyable, not just functional. Explicitly check the Vertical Slice playtest report.
+- [ ] UX specs cover all UI Requirements sections from MVP-tier GDDs
+- [ ] Interaction pattern library documents patterns used in key screens
+- [ ] Accessibility tier from `design/accessibility-requirements.md` is addressed in all key screen UX specs
+- [ ] Sprint plan references real story file paths from `production/epics/`
+      (not just GDDs — stories must embed GDD req ID + ADR reference)
+- [ ] **Vertical Slice is COMPLETE**, not just scoped — the build demonstrates the full core loop end-to-end. At least one complete [start → challenge → resolution] cycle works.
+- [ ] Architecture document has no unresolved open questions in Foundation or Core layers
+- [ ] All ADRs have Engine Compatibility sections stamped with the engine version
+- [ ] All ADRs have ADR Dependencies sections (even if all fields are "None")
+- [ ] `/bmad-bmm-check-implementation-readiness` has been run or equivalent manual
+      validation confirms GDDs + architecture + epics are coherent
+- [ ] **Core fantasy is delivered** — at least one playtester independently described an experience that matches the Player Fantasy section of the core system GDDs (without being prompted).
+
+**Vertical Slice Validation** (FAIL if any item is NO):
+- [ ] A human has played through the core loop without developer guidance
+- [ ] The game communicates what to do within the first 2 minutes of play
+- [ ] No critical "fun blocker" bugs exist in the Vertical Slice build
+- [ ] The core mechanic feels good to interact with (this is a subjective check — ask the user)
+
+> **Note**: If any Vertical Slice Validation item is FAIL, the verdict is automatically FAIL
+> regardless of other checks. Advancing without a validated Vertical Slice is the #1 cause of
+> production failure in game development (per GDC postmortem data from 155 projects).
 
 ---
 
@@ -102,13 +159,21 @@ The project progresses through these stages:
 - [ ] All core mechanics from GDD are implemented (cross-reference `design/gdd/` with `src/`)
 - [ ] Main gameplay path is playable end-to-end
 - [ ] Test files exist in `tests/`
-- [ ] At least 1 playtest report (or `/playtest-report` has been run)
+- [ ] At least 3 distinct playtest sessions documented in `production/playtests/`
+- [ ] Playtest reports cover: new player experience, mid-game systems, and difficulty curve
+- [ ] Fun hypothesis from Game Concept has been explicitly validated or revised
 
 **Quality Checks:**
 - [ ] Tests are passing (run test suite via Bash)
 - [ ] No critical/blocker bugs in any bug tracker or known issues
 - [ ] Core loop plays as designed (compare to GDD acceptance criteria)
 - [ ] Performance is within budget (check technical-preferences.md targets)
+- [ ] Playtest findings have been reviewed and critical fun issues addressed (not just documented)
+- [ ] No "confusion loops" identified — no point in the game where >50% of playtesters got stuck without knowing why
+- [ ] Difficulty curve matches the Difficulty Curve design doc (if one exists at `design/difficulty-curve.md`)
+- [ ] All implemented screens have corresponding UX specs (no "designed in-code" screens)
+- [ ] Interaction pattern library is up-to-date with all patterns used in implementation
+- [ ] Accessibility compliance verified against committed tier in `design/accessibility-requirements.md`
 
 ---
 
@@ -229,9 +294,26 @@ Based on the verdict, suggest specific next steps:
 - **No game concept?** → `/brainstorm` to create one
 - **No systems index?** → `/map-systems` to decompose the concept into systems
 - **Missing design docs?** → `/reverse-document` or delegate to `game-designer`
-- **Missing ADRs?** → `/architecture-decision`
+- **Small design change needed?** → `/quick-design` for changes under ~4 hours (bypasses full GDD pipeline)
+- **No UX specs?** → `/ux-design [screen name]` to author specs, or `/team-ui [feature]` for full pipeline
+- **UX specs not reviewed?** → `/ux-review [file]` or `/ux-review all` to validate
+- **No accessibility requirements doc?** → create `design/accessibility-requirements.md` using the accessibility-requirements template
+- **No interaction pattern library?** → `/ux-design patterns` to initialize it
+- **GDDs not cross-reviewed?** → `/review-all-gdds` (run after all MVP GDDs are individually approved)
+- **Cross-GDD consistency issues?** → fix flagged GDDs, then re-run `/review-all-gdds`
+- **Missing ADRs?** → `/architecture-decision` for individual decisions
+- **No master architecture doc?** → `/create-architecture` for the full blueprint
+- **ADRs missing engine compatibility sections?** → Re-run `/architecture-decision`
+  or manually add Engine Compatibility sections to existing ADRs
+- **Missing control manifest?** → `/create-control-manifest` (requires Accepted ADRs)
+- **Missing epics/stories?** → `/create-epics-stories all` (requires control manifest)
+- **Stories not implementation-ready?** → `/story-readiness` to validate stories before developers pick them up
 - **Tests failing?** → delegate to `lead-programmer` or `qa-tester`
 - **No playtest data?** → `/playtest-report`
+- **Less than 3 playtest sessions?** → Run more playtests before advancing. Use `/playtest-report` to structure findings.
+- **No Difficulty Curve doc?** → Consider creating one at `design/difficulty-curve.md` before polish
+- **No player journey document?** → create `design/player-journey.md` using the player journey template
+- **Need a quick sprint check?** → `/sprint-status` for current sprint progress snapshot
 - **Performance unknown?** → `/perf-profile`
 - **Not localized?** → `/localize`
 - **Ready for release?** → `/launch-checklist`