plan: Phase 8 DAG System TDD with 2 plans

- 08-01: GameDAGRouter edge cases and anchor validation TDD (17+ tests)
- 08-02: Performance with large datasets (10K+ games) and diversity coverage TDD

TDD discipline: tests define correctness, code must match.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

.planning/STATE.md

@@ -10,9 +10,9 @@ See: .planning/PROJECT.md (updated 2026-01-10)
 ## Current Position
 
 Phase: 8 of 12 (DAG System TDD)
-Plan: Not started
-Status: Ready to plan
-Last activity: 2026-01-10 — Milestone v1.1 TDD & Correctness created
+Plan: 08-01 ready (2 plans total)
+Status: Ready to execute
+Last activity: 2026-01-10 — Phase 8 planned (2 TDD plans)
 
 Progress: ░░░░░░░░░░ 0%
 
@@ -43,6 +43,6 @@ None.
 ## Session Continuity
 
 Last session: 2026-01-10
-Stopped at: Milestone v1.1 initialization
+Stopped at: Phase 8 planning complete
 Resume file: None
-Next action: /gsd:plan-phase 8 to plan first phase
+Next action: /gsd:execute-plan 08-01 to start TDD execution