refactor: extract/ingest facade, merge_one, deduplicate ops constants

- Add bincio/extract/ingest.py as a facade over the extract internals (ingest_parsed, strava_sync), reducing coupling from 6+ imports to one
  - Add merge_one() to merge.py — fast single-activity path for interactive edits (rewrites one file + index, skips full directory rebuild)
  - Rewrite edit/ops.py to delegate to the new facade; fix broken run_strava_sync return (was referencing undefined locals)
  - Remove duplicated SPORTS, STAT_PANELS, VALID_ACTIVITY_ID from edit/server.py — now imported from ops.py

bincio/render/merge.py

@@ -74,6 +74,84 @@ def _apply_sidecar_summary(summary: dict, fm: dict) -> dict:
     return s
 
 
+def merge_one(data_dir: Path, activity_id: str) -> None:
+    """Apply (or remove) sidecar overrides for a single activity.
+
+    Updates data_dir/_merged/activities/{id}.json and rewrites
+    _merged/index.json.  Faster than merge_all() for interactive edits
+    because it touches only one activity file instead of rebuilding the
+    whole _merged/activities/ directory.
+
+    Use merge_all() for bulk operations (first run, Strava sync, etc.).
+    """
+    edits_dir  = data_dir / "edits"
+    acts_dir   = data_dir / "activities"
+    merged_dir = data_dir / "_merged"
+    merged_acts = merged_dir / "activities"
+    merged_acts.mkdir(parents=True, exist_ok=True)
+
+    src = acts_dir / f"{activity_id}.json"
+    if not src.exists():
+        return
+
+    dest = merged_acts / f"{activity_id}.json"
+
+    # Determine if a sidecar or image list applies to this activity
+    sidecar_path = edits_dir / f"{activity_id}.md" if edits_dir.exists() else None
+    images_dir   = edits_dir / "images" / activity_id if edits_dir.exists() else None
+    has_sidecar  = sidecar_path is not None and sidecar_path.exists()
+    image_files: list[str] = []
+    if images_dir and images_dir.exists():
+        image_files = sorted(
+            p.name for p in images_dir.iterdir()
+            if p.is_file() and not p.name.startswith(".")
+        )
+
+    needs_merge = has_sidecar or bool(image_files)
+
+    # Remove the old dest (symlink or file) before writing the new one
+    if dest.exists() or dest.is_symlink():
+        dest.unlink()
+
+    if needs_merge:
+        detail = json.loads(src.read_text(encoding="utf-8"))
+        if has_sidecar:
+            fm, body = parse_sidecar(sidecar_path)  # type: ignore[arg-type]
+            detail = apply_sidecar(detail, fm, body)
+        if image_files:
+            detail["custom"] = dict(detail.get("custom") or {})
+            detail["custom"]["images"] = image_files
+        dest.write_text(json.dumps(detail, indent=2, ensure_ascii=False))
+    else:
+        dest.symlink_to(src.resolve())
+
+    # Rewrite index — load the full sidecar map so all summaries stay consistent
+    index_path = data_dir / "index.json"
+    if not index_path.exists():
+        return
+
+    all_sidecars: dict[str, tuple[dict, str]] = {}
+    if edits_dir and edits_dir.exists():
+        for md_path in edits_dir.glob("*.md"):
+            all_sidecars[md_path.stem] = parse_sidecar(md_path)
+
+    index = json.loads(index_path.read_text(encoding="utf-8"))
+    activities = []
+    for s in index.get("activities", []):
+        aid = s.get("id", "")
+        if aid in all_sidecars:
+            fm, _ = all_sidecars[aid]
+            s = _apply_sidecar_summary(s, fm)
+        activities.append(s)
+
+    activities = [a for a in activities if a.get("privacy") != "private"]
+    activities.sort(key=lambda a: a.get("started_at", ""), reverse=True)
+    activities.sort(key=lambda a: 0 if a.get("custom", {}).get("highlight") else 1)
+
+    index["activities"] = activities
+    (merged_dir / "index.json").write_text(json.dumps(index, indent=2, ensure_ascii=False))
+
+
 def merge_all(data_dir: Path) -> int:
     """Build data_dir/_merged/ with all sidecar overrides applied.