docs: create roadmap (5 phases)

.planning/STATE.md

@@ -0,0 +1,102 @@
+# STATE: Super Pong Next Gen
+
+**Project Reference**
+- **Core Value:** Pong reimagined with juice and depth — spectacular visuals, rich mechanics, complete game experience
+- **Current Focus:** Roadmap created, ready for Phase 1 planning
+- **Key Constraint:** Coarse granularity (5 phases max), HTML5 Canvas + vanilla JS, static deployment
+
+---
+
+## Current Position
+
+| Attribute | Value |
+|-----------|-------|
+| **Phase** | Planning complete, ready to plan Phase 1 |
+| **Plan** | None active yet |
+| **Status** | Roadmap finalized, 37/37 requirements mapped |
+| **Progress** | 0% (0 phases complete) |
+
+```
+[                    ] 0% — Roadmap → Phase 1 planning
+```
+
+---
+
+## Performance Metrics
+
+| Metric | Target | Status |
+|--------|--------|--------|
+| **Phase Coverage** | 100% (37/37 requirements mapped) | ✓ Complete |
+| **Success Criteria** | 2-5 per phase | ✓ Complete |
+| **Dependency Chain** | Linear (P1 → P2 → P3 → P4 → P5) | ✓ Validated |
+
+---
+
+## Accumulated Context
+
+### Key Decisions Made
+
+1. **Coarse Granularity Compression:** Research suggested 10 phases; compressed to 5 by merging:
+   - Game loop + input + physics = Phase 1
+   - Second paddle + AI = Phase 2
+   - Menus + audio + pause = Phase 3
+   - Visual effects + power-ups + arenas = Phase 4
+   - Performance + testing = Phase 5
+
+2. **Phase 5 (Release) Has No Requirements:** All 37 v1 requirements covered by phases 1-4. Phase 5 is purely validation (cross-browser, performance, pitfall mitigation).
+
+3. **Success Criteria Grounded in Research Pitfalls:** Each phase's criteria address critical pitfalls from research:
+   - Phase 1: DPI scaling, game loop timing
+   - Phase 2: Ball tunneling, input lag, AI balance
+   - Phase 3: Audio autoplay policy
+   - Phase 4: Power-up balance
+   - Phase 5: Performance, memory leaks, cross-browser
+
+### Coverage Validation
+
+**Total v1 Requirements:** 37
+- CORE (8): All mapped to Phase 1-2
+- AI (4): All mapped to Phase 2
+- SCRN (4): All mapped to Phase 3
+- VFX (5): All mapped to Phase 1 (DPI) and Phase 4 (particles/glow/trails/shake)
+- PWR (7): All mapped to Phase 4
+- ARENA (4): All mapped to Phase 4
+- AUD (5): All mapped to Phase 3
+
+**Unmapped Requirements:** 0 ✓
+**Coverage:** 100% ✓
+
+### Research Alignment
+
+- Phase 1 addresses Research Pitfalls: #1 (Game Loop Timing), #2 (Canvas DPI Scaling)
+- Phase 2 addresses Research Pitfalls: #3 (Ball Tunneling), #4 (Input Lag), #5 (AI Difficulty Balance)
+- Phase 3 addresses Research Pitfall: #6 (WebAudio Autoplay Policy)
+- Phase 4 addresses Research Pitfalls: #7 (Power-Up Balance)
+- Phase 5 addresses Research Pitfall: #8 (Memory Leaks)
+
+---
+
+## Session Continuity
+
+### What Just Happened
+
+Roadmap derived from 37 v1 requirements organized into 5 phases, each with 2-5 observable success criteria. Granularity set to coarse; 10-phase research recommendation compressed by grouping related technical work.
+
+### What Comes Next
+
+1. `/gsd:plan-phase 1` — Decompose Phase 1 into executable plans
+2. Continue through phases 2-5
+3. Execute plans in dependency order
+4. Validate success criteria at each phase completion
+
+### Known Blockers
+
+None. All context available, all requirements mapped, roadmap ready for planning.
+
+### Decisions Pending
+
+None. Roadmap finalized; awaiting user approval before phase planning begins.
+
+---
+
+*State initialized: 2026-03-10*