docs: Archive historical documentation (26 files → doc/archive/)

Moved completed/historical docs to doc/archive/ for cleaner context:

Archived (26 files):
- Analysis docs: variable tempo, audio architecture, build optimization
- Handoff docs: 6 agent handoff documents
- Debug reports: shadows, peak meter, timing fixes
- Task summaries and planning docs

Kept (16 files):
- Essential: AI_RULES, HOWTO, CONTRIBUTING, CONTEXT_MAINTENANCE
- Active subsystems: 3D, ASSET_SYSTEM, TRACKER, SEQUENCE
- Current work: MASKING_SYSTEM, SPECTRAL_BRUSH_EDITOR

Updated COMPLETED.md with archive index for easy reference.

27 files changed, 27 insertions, 0 deletions

diff --git a/doc/COMPLETED.md b/doc/COMPLETED.md
index a4e6a94..a3c173d 100644
--- a/doc/COMPLETED.md
+++ b/doc/COMPLETED.md
@@ -2,6 +2,33 @@
 
 This file tracks recently completed tasks, organized by completion date.
 
+## Archive Index
+
+Detailed historical documents have been moved to `doc/archive/` for reference:
+
+**Analysis & Architecture:**
+- ANALYSIS_VARIABLE_TEMPO.md, ANALYSIS_VARIABLE_TEMPO_V2.md
+- AUDIO_LIFECYCLE_REFACTOR.md, AUDIO_TIMING_ARCHITECTURE.md
+- BUILD_OPTIMIZATION_PROPOSAL.md, BUILD_OPTIMIZATION_PROPOSAL_V2.md
+- PLATFORM_ANALYSIS.md, SHADER_PARAMETRIZATION_PLAN.md
+
+**Handoffs & Summaries:**
+- HANDOFF.md, HANDOFF_2026-02-04.md, HANDOFF_2026-02-08.md, HANDOFF_CLAUDE.md
+- HANDOFF_SCENE_LOADER.md, HANDOFF_SPECTRAL_EDITOR.md
+- PLATFORM_SIDE_QUEST_SUMMARY.md, TASKS_SUMMARY.md
+
+**Debug Reports:**
+- DEBUG_SHADOWS.md, PEAK_FIX_SUMMARY.md, PEAK_METER_DEBUG.md
+- SAMPLE_ACCURATE_TIMING_FIX.md, VISUAL_DEBUG.md
+
+**Testing & Reports:**
+- FINAL_STRIP_REPORT.md, GPU_EFFECTS_TEST_ANALYSIS.md
+
+**Planning Docs:**
+- PHASE2_COMPRESSION.md, SPEC_EDITOR.md, STRIPPING.md
+
+Use `read @doc/archive/FILENAME.md` to access archived documents.
+
 ## Recently Completed (February 8, 2026)
 
 - [x] **Shader Parametrization System (Task #73 Phase 0)** (February 8, 2026)
diff --git a/doc/ANALYSIS_VARIABLE_TEMPO.md b/doc/archive/ANALYSIS_VARIABLE_TEMPO.md
index f09996b..f09996b 100644
--- a/doc/ANALYSIS_VARIABLE_TEMPO.md
+++ b/doc/archive/ANALYSIS_VARIABLE_TEMPO.md
diff --git a/doc/ANALYSIS_VARIABLE_TEMPO_V2.md b/doc/archive/ANALYSIS_VARIABLE_TEMPO_V2.md
index add347c..add347c 100644
--- a/doc/ANALYSIS_VARIABLE_TEMPO_V2.md
+++ b/doc/archive/ANALYSIS_VARIABLE_TEMPO_V2.md
diff --git a/doc/AUDIO_LIFECYCLE_REFACTOR.md b/doc/archive/AUDIO_LIFECYCLE_REFACTOR.md
index f5e0045..f5e0045 100644
--- a/doc/AUDIO_LIFECYCLE_REFACTOR.md
+++ b/doc/archive/AUDIO_LIFECYCLE_REFACTOR.md
diff --git a/doc/AUDIO_TIMING_ARCHITECTURE.md b/doc/archive/AUDIO_TIMING_ARCHITECTURE.md
index 7b125d0..7b125d0 100644
--- a/doc/AUDIO_TIMING_ARCHITECTURE.md
+++ b/doc/archive/AUDIO_TIMING_ARCHITECTURE.md
diff --git a/doc/BUILD_OPTIMIZATION_PROPOSAL.md b/doc/archive/BUILD_OPTIMIZATION_PROPOSAL.md
index 8d61e10..8d61e10 100644
--- a/doc/BUILD_OPTIMIZATION_PROPOSAL.md
+++ b/doc/archive/BUILD_OPTIMIZATION_PROPOSAL.md
diff --git a/doc/BUILD_OPTIMIZATION_PROPOSAL_V2.md b/doc/archive/BUILD_OPTIMIZATION_PROPOSAL_V2.md
index 315911a..315911a 100644
--- a/doc/BUILD_OPTIMIZATION_PROPOSAL_V2.md
+++ b/doc/archive/BUILD_OPTIMIZATION_PROPOSAL_V2.md
diff --git a/doc/DEBUG_SHADOWS.md b/doc/archive/DEBUG_SHADOWS.md
index bcf6d3e..bcf6d3e 100644
--- a/doc/DEBUG_SHADOWS.md
+++ b/doc/archive/DEBUG_SHADOWS.md
diff --git a/doc/FINAL_STRIP_REPORT.md b/doc/archive/FINAL_STRIP_REPORT.md
index 6ed1b43..6ed1b43 100644
--- a/doc/FINAL_STRIP_REPORT.md
+++ b/doc/archive/FINAL_STRIP_REPORT.md
diff --git a/doc/GPU_EFFECTS_TEST_ANALYSIS.md b/doc/archive/GPU_EFFECTS_TEST_ANALYSIS.md
index 31399b5..31399b5 100644
--- a/doc/GPU_EFFECTS_TEST_ANALYSIS.md
+++ b/doc/archive/GPU_EFFECTS_TEST_ANALYSIS.md
diff --git a/doc/HANDOFF.md b/doc/archive/HANDOFF.md
index bc22314..bc22314 100644
--- a/doc/HANDOFF.md
+++ b/doc/archive/HANDOFF.md
diff --git a/doc/HANDOFF_2026-02-04.md b/doc/archive/HANDOFF_2026-02-04.md
index f38e5be..f38e5be 100644
--- a/doc/HANDOFF_2026-02-04.md
+++ b/doc/archive/HANDOFF_2026-02-04.md
diff --git a/doc/HANDOFF_2026-02-08.md b/doc/archive/HANDOFF_2026-02-08.md
index f796f05..f796f05 100644
--- a/doc/HANDOFF_2026-02-08.md
+++ b/doc/archive/HANDOFF_2026-02-08.md
diff --git a/doc/HANDOFF_CLAUDE.md b/doc/archive/HANDOFF_CLAUDE.md
index 24de0b1..24de0b1 100644
--- a/doc/HANDOFF_CLAUDE.md
+++ b/doc/archive/HANDOFF_CLAUDE.md
diff --git a/doc/HANDOFF_SCENE_LOADER.md b/doc/archive/HANDOFF_SCENE_LOADER.md
index b218d0b..b218d0b 100644
--- a/doc/HANDOFF_SCENE_LOADER.md
+++ b/doc/archive/HANDOFF_SCENE_LOADER.md
diff --git a/doc/HANDOFF_SPECTRAL_EDITOR.md b/doc/archive/HANDOFF_SPECTRAL_EDITOR.md
index 97d9f98..97d9f98 100644
--- a/doc/HANDOFF_SPECTRAL_EDITOR.md
+++ b/doc/archive/HANDOFF_SPECTRAL_EDITOR.md
diff --git a/doc/PEAK_FIX_SUMMARY.md b/doc/archive/PEAK_FIX_SUMMARY.md
index cf42233..cf42233 100644
--- a/doc/PEAK_FIX_SUMMARY.md
+++ b/doc/archive/PEAK_FIX_SUMMARY.md
diff --git a/doc/PEAK_METER_DEBUG.md b/doc/archive/PEAK_METER_DEBUG.md
index 002180c..002180c 100644
--- a/doc/PEAK_METER_DEBUG.md
+++ b/doc/archive/PEAK_METER_DEBUG.md
diff --git a/doc/PHASE2_COMPRESSION.md b/doc/archive/PHASE2_COMPRESSION.md
index 3c83fa4..3c83fa4 100644
--- a/doc/PHASE2_COMPRESSION.md
+++ b/doc/archive/PHASE2_COMPRESSION.md
diff --git a/doc/PLATFORM_ANALYSIS.md b/doc/archive/PLATFORM_ANALYSIS.md
index eefbd42..eefbd42 100644
--- a/doc/PLATFORM_ANALYSIS.md
+++ b/doc/archive/PLATFORM_ANALYSIS.md
diff --git a/doc/PLATFORM_SIDE_QUEST_SUMMARY.md b/doc/archive/PLATFORM_SIDE_QUEST_SUMMARY.md
index d4be581..d4be581 100644
--- a/doc/PLATFORM_SIDE_QUEST_SUMMARY.md
+++ b/doc/archive/PLATFORM_SIDE_QUEST_SUMMARY.md
diff --git a/doc/SAMPLE_ACCURATE_TIMING_FIX.md b/doc/archive/SAMPLE_ACCURATE_TIMING_FIX.md
index 6399090..6399090 100644
--- a/doc/SAMPLE_ACCURATE_TIMING_FIX.md
+++ b/doc/archive/SAMPLE_ACCURATE_TIMING_FIX.md
diff --git a/doc/SHADER_PARAMETRIZATION_PLAN.md b/doc/archive/SHADER_PARAMETRIZATION_PLAN.md
index f5afa27..f5afa27 100644
--- a/doc/SHADER_PARAMETRIZATION_PLAN.md
+++ b/doc/archive/SHADER_PARAMETRIZATION_PLAN.md
diff --git a/doc/SPEC_EDITOR.md b/doc/archive/SPEC_EDITOR.md
index 497a5a2..497a5a2 100644
--- a/doc/SPEC_EDITOR.md
+++ b/doc/archive/SPEC_EDITOR.md
diff --git a/doc/STRIPPING.md b/doc/archive/STRIPPING.md
index 7e69177..7e69177 100644
--- a/doc/STRIPPING.md
+++ b/doc/archive/STRIPPING.md
diff --git a/doc/TASKS_SUMMARY.md b/doc/archive/TASKS_SUMMARY.md
index 77cde6b..77cde6b 100644
--- a/doc/TASKS_SUMMARY.md
+++ b/doc/archive/TASKS_SUMMARY.md
diff --git a/doc/VISUAL_DEBUG.md b/doc/archive/VISUAL_DEBUG.md
index f0adcba..f0adcba 100644
--- a/doc/VISUAL_DEBUG.md
+++ b/doc/archive/VISUAL_DEBUG.md