docs(12-01): complete SRT Processing Module plan

- Create 12-01-SUMMARY.md with implementation details
- Update STATE.md with current position (Phase 12, 50% complete)
- Update ROADMAP.md with plan progress
- Mark requirements SRT-01~04, OUT-01~02, OUT-04 as complete

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

.planning/STATE.md

@@ -2,9 +2,9 @@
 gsd_state_version: 1.0
 milestone: v1.5
 milestone_name: B站字幕简化处理
-status: planning
-last_updated: "2026-03-19T00:00:00.000Z"
-last_activity: 2026-03-19 — Milestone v1.5 started
+status: in_progress
+last_updated: "2026-03-19T15:45:00.000Z"
+last_activity: 2026-03-19 — Completed 12-01 SRT Processing Module
 ---
 
 # Project State
@@ -14,16 +14,16 @@ last_activity: 2026-03-19 — Milestone v1.5 started
 See: .planning/PROJECT.md (updated 2026-03-19)
 
 **Core value:** 可靠、可维护的处理管道 - 每个步骤独立、可验证、可恢复
-**Current focus:** Defining requirements for v1.5
+**Current focus:** Phase 12 - SRT 简化处理器
 
 ## Current Position
 
-Phase: Not started (defining requirements)
-Plan: —
-Status: Defining requirements
-Last activity: 2026-03-19 — Milestone v1.5 started
+Phase: 12-srt-simplifier (1/2 plans complete)
+Plan: 12-02
+Status: In progress
+Last activity: 2026-03-19 — Completed 12-01 SRT Processing Module
 
-Progress: [░░░░░░░░░░] 0%
+Progress: [█████░░░░░] 50%
 
 ## Accumulated Context
 
@@ -41,6 +41,12 @@ v1.5 scope:
 - 简化流程：SRT → 去时间戳 → 分段 → 纠正 → Markdown
 - 移除深度观点分析
 
+v1.5 Phase 12 decisions:
+- TDD approach with RED-GREEN cycles for all modules
+- Lazy import for ASRCorrector to avoid dependency issues
+- Simple rule-based segmentation (no LLM) for speed
+- ASR correction is optional, fallback to original text
+
 ### Blockers/Concerns
 
 None.
@@ -48,7 +54,7 @@ None.
 ## Session Continuity
 
 Last session: 2026-03-19
-Stopped at: Starting v1.5 milestone planning
+Stopped at: Completed 12-01 SRT Processing Module
 Resume file: None
 
-**Next step:** Define requirements and create roadmap
+**Next step:** Execute 12-02 Pipeline Integration