feat: Wired source_videos and body_sections_format into technique detai…

- "backend/routers/techniques.py"

GSD-Task: S03/T02

.gsd/milestones/M014/slices/S03/S03-PLAN.md

@@ -45,7 +45,7 @@ This is the data layer foundation — migration file, model changes, and schema
   - Estimate: 30m
   - Files: alembic/versions/012_multi_source_format.py, backend/models.py, backend/schemas.py
   - Verify: cd backend && python -c "from models import TechniquePageVideo, TechniquePage; assert hasattr(TechniquePage, 'body_sections_format'); print('models OK')" && python -c "from schemas import SourceVideoSummary, TechniquePageDetail; print('schemas OK')"
-- [ ] **T02: Wire source_videos into technique detail endpoint** — Update the technique detail endpoint to eagerly load source_video_links and build the source_videos list on the response. Verify end-to-end with an API call.
+- [x] **T02: Wired source_videos and body_sections_format into technique detail API response with eager-loaded association table** — Update the technique detail endpoint to eagerly load source_video_links and build the source_videos list on the response. Verify end-to-end with an API call.
 
 ## Steps
 

.gsd/milestones/M014/slices/S03/tasks/T01-VERIFY.json

@@ -0,0 +1,16 @@
+{
+  "schemaVersion": 1,
+  "taskId": "T01",
+  "unitId": "M014/S03/T01",
+  "timestamp": 1775178991056,
+  "passed": true,
+  "discoverySource": "task-plan",
+  "checks": [
+    {
+      "command": "cd backend",
+      "exitCode": 0,
+      "durationMs": 5,
+      "verdict": "pass"
+    }
+  ]
+}

.gsd/milestones/M014/slices/S03/tasks/T02-SUMMARY.md

@@ -0,0 +1,77 @@
+---
+id: T02
+parent: S03
+milestone: M014
+provides: []
+requires: []
+affects: []
+key_files: ["backend/routers/techniques.py"]
+key_decisions: []
+patterns_established: []
+drill_down_paths: []
+observability_surfaces: []
+duration: ""
+verification_result: "Alembic migration 012 ran clean. API response for existing technique shows body_sections_format: "v1" and source_videos: []. Tested via both Docker internal curl and external ub01:8096 URL."
+completed_at: 2026-04-03T01:19:28.974Z
+blocker_discovered: false
+---
+
+# T02: Wired source_videos and body_sections_format into technique detail API response with eager-loaded association table
+
+> Wired source_videos and body_sections_format into technique detail API response with eager-loaded association table
+
+## What Happened
+---
+id: T02
+parent: S03
+milestone: M014
+key_files:
+  - backend/routers/techniques.py
+key_decisions:
+  - (none)
+duration: ""
+verification_result: passed
+completed_at: 2026-04-03T01:19:28.974Z
+blocker_discovered: false
+---
+
+# T02: Wired source_videos and body_sections_format into technique detail API response with eager-loaded association table
+
+**Wired source_videos and body_sections_format into technique detail API response with eager-loaded association table**
+
+## What Happened
+
+Updated get_technique() in backend/routers/techniques.py to eagerly load source_video_links relationship chained to source_video via selectinload. Built source_videos list from association table rows with content_type enum handling. Added imports for TechniquePageVideo and SourceVideoSummary. Deployed to ub01, ran Alembic migration 012, and verified API response includes both new fields with correct defaults.
+
+## Verification
+
+Alembic migration 012 ran clean. API response for existing technique shows body_sections_format: "v1" and source_videos: []. Tested via both Docker internal curl and external ub01:8096 URL.
+
+## Verification Evidence
+
+| # | Command | Exit Code | Verdict | Duration |
+|---|---------|-----------|---------|----------|
+| 1 | `cd backend && python -c "from models import TechniquePageVideo, TechniquePage; assert hasattr(TechniquePage, 'body_sections_format'); print('models OK')"` | 0 | ✅ pass | 500ms |
+| 2 | `cd backend && python -c "from schemas import SourceVideoSummary, TechniquePageDetail; print('schemas OK')"` | 0 | ✅ pass | 400ms |
+| 3 | `ssh ub01 'docker exec chrysopedia-api alembic upgrade head'` | 0 | ✅ pass | 2000ms |
+| 4 | `ssh ub01 'curl -s http://ub01:8096/api/v1/techniques/parallel-stereo-processing-keota | python3 -m json.tool | grep -E body_sections_format|source_videos'` | 0 | ✅ pass | 1000ms |
+
+
+## Deviations
+
+None.
+
+## Known Issues
+
+None.
+
+## Files Created/Modified
+
+- `backend/routers/techniques.py`
+
+
+## Deviations
+None.
+
+## Known Issues
+None.

backend/routers/techniques.py

@@ -11,12 +11,13 @@ from sqlalchemy.ext.asyncio import AsyncSession
 from sqlalchemy.orm import selectinload
 
 from database import get_session
-from models import Creator, KeyMoment, RelatedTechniqueLink, SourceVideo, TechniquePage, TechniquePageVersion
+from models import Creator, KeyMoment, RelatedTechniqueLink, SourceVideo, TechniquePage, TechniquePageVersion, TechniquePageVideo
 from schemas import (
     CreatorInfo,
     KeyMomentSummary,
     PaginatedResponse,
     RelatedLinkItem,
+    SourceVideoSummary,
     TechniquePageDetail,
     TechniquePageRead,
     TechniquePageVersionDetail,
@@ -223,6 +224,9 @@ async def get_technique(
             selectinload(TechniquePage.incoming_links).selectinload(
                 RelatedTechniqueLink.source_page
             ),
+            selectinload(TechniquePage.source_video_links).selectinload(
+                TechniquePageVideo.source_video
+            ),
         )
     )
     result = await db.execute(stmt)
@@ -295,12 +299,25 @@ async def get_technique(
     version_count_result = await db.execute(version_count_stmt)
     version_count = version_count_result.scalar() or 0
 
+    # Build source video list from association table
+    source_videos = [
+        SourceVideoSummary(
+            id=link.source_video.id,
+            filename=link.source_video.filename,
+            content_type=link.source_video.content_type.value if hasattr(link.source_video.content_type, 'value') else str(link.source_video.content_type),
+            added_at=link.added_at,
+        )
+        for link in page.source_video_links
+        if link.source_video is not None
+    ]
+
     return TechniquePageDetail(
         **base.model_dump(),
         key_moments=key_moment_items,
         creator_info=creator_info,
         related_links=related_links,
         version_count=version_count,
+        source_videos=source_videos,
     )