Segments Phase 4: detail page, activity efforts, athlete tab, new APIs

New API endpoints:
- GET /api/segments/{id} — single segment metadata
- GET /api/activities/{id}/segment_efforts — efforts for an activity (auth)
- GET /api/users/{handle}/segment_summary — public best time + count per segment

New components:
- SegmentDetail.svelte — map + metadata + effort table (with PR/Δ) + rescan button
- SegmentsPage.svelte — URL router: shows detail when /segments/{id}/, list otherwise

Updated:
- segments/index.astro — now uses SegmentsPage router
- nginx-activity.conf — add /segments/ try_files rule for client-side routing
- ActivityDetail.svelte — segment efforts block below laps
- AthleteView.svelte — Segments tab with best time + effort count per segment
- format.ts — add formatElapsed() for compact m:ss display

bincio/serve/server.py

@@ -2437,6 +2437,25 @@ async def get_segments(
     } for s in segs])
 
 
+@app.get("/api/segments/{segment_id}")
+async def get_segment(segment_id: str) -> JSONResponse:
+    """Return metadata for a single segment."""
+    dd = _get_data_dir()
+    seg = _seg_store.load_segment(dd, segment_id)
+    if seg is None:
+        raise HTTPException(404, "Segment not found")
+    return JSONResponse({
+        "id":          seg.id,
+        "name":        seg.name,
+        "sport":       seg.sport,
+        "polyline":    seg.polyline,
+        "distance_m":  seg.distance_m,
+        "bbox":        seg.bbox,
+        "created_by":  seg.created_by,
+        "created_at":  _seg_store._iso(seg.created_at),
+    })
+
+
 @app.post("/api/segments")
 async def create_segment(
     body: CreateSegmentRequest,
@@ -2565,6 +2584,70 @@ async def trigger_detect(
     return JSONResponse({"ok": True, "efforts_found": total})
 
 
+@app.get("/api/activities/{activity_id}/segment_efforts")
+async def activity_segment_efforts(
+    activity_id: str,
+    bincio_session: Optional[str] = Cookie(default=None),
+) -> JSONResponse:
+    """Return segment efforts that belong to a specific activity for the logged-in user."""
+    user = _require_user(bincio_session)
+    dd = _get_data_dir()
+    efforts_dir = dd / user.handle / "segment_efforts"
+    result = []
+    if efforts_dir.exists():
+        import json as _json
+        for ef_file in sorted(efforts_dir.glob("*.json")):
+            seg_id = ef_file.stem
+            all_efforts = _seg_store.load_efforts(dd, user.handle, seg_id)
+            matching = [e for e in all_efforts if e.activity_id == activity_id]
+            if not matching:
+                continue
+            seg = _seg_store.load_segment(dd, seg_id)
+            if not seg:
+                continue
+            pr_elapsed = min(e.elapsed_s for e in all_efforts)
+            for eff in matching:
+                result.append({
+                    "segment_id":       seg.id,
+                    "segment_name":     seg.name,
+                    "segment_distance_m": seg.distance_m,
+                    "elapsed_s":        eff.elapsed_s,
+                    "pr_elapsed_s":     pr_elapsed,
+                    "started_at":       _seg_store._iso(eff.started_at),
+                })
+    return JSONResponse(result)
+
+
+@app.get("/api/users/{handle}/segment_summary")
+async def user_segment_summary(handle: str) -> JSONResponse:
+    """Public endpoint: segments where this user has efforts, with best time and count."""
+    dd = _get_data_dir()
+    efforts_dir = dd / handle / "segment_efforts"
+    result = []
+    if efforts_dir.exists():
+        for ef_file in sorted(efforts_dir.glob("*.json")):
+            seg_id = ef_file.stem
+            efforts = _seg_store.load_efforts(dd, handle, seg_id)
+            if not efforts:
+                continue
+            seg = _seg_store.load_segment(dd, seg_id)
+            if not seg:
+                continue
+            best = min(efforts, key=lambda e: e.elapsed_s)
+            result.append({
+                "segment": {
+                    "id":         seg.id,
+                    "name":       seg.name,
+                    "sport":      seg.sport,
+                    "distance_m": seg.distance_m,
+                },
+                "best_elapsed_s": best.elapsed_s,
+                "effort_count":   len(efforts),
+            })
+    result.sort(key=lambda x: x["segment"]["name"].lower())
+    return JSONResponse(result)
+
+
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