Records: apply sidecars before computing; fix best_climb_m for long mountain climbs

- _rebuild_athlete_json now applies sidecar edits (sub_sport, sport, etc.)
  in-memory before passing summaries to write_athlete_json, so activities
  marked indoor via sidecar are correctly excluded from records.

- _best_climb now runs Kadane's over cumulative distance (not 1Hz dense
  time) so recording pauses don't create None gaps that falsely reset the
  climbing window. Grappa: 811m→1603m; Nivolet: 311m→2009m.

- Add bincio render --recompute-climbs to backfill existing activities
  from their stored timeseries.

bincio/render/cli.py

@@ -106,9 +106,14 @@ def _bake_tracks(data: Path, handle: str | None = None) -> None:
 
 
 def _rebuild_athlete_json(data: Path, handle: str | None = None) -> None:
-    """Rebuild athlete.json for one user or all users from their current index.json."""
+    """Rebuild athlete.json for one user or all users.
+
+    Reads raw index.json summaries, applies any sidecar edits in-memory (so
+    overrides like sub_sport: indoor are respected), then calls write_athlete_json.
+    """
     import json
     from bincio.extract.writer import write_athlete_json
+    from bincio.render.merge import parse_sidecar, _apply_sidecar_summary
 
     targets = [data / handle] if handle else _user_dirs(data)
     _COMPUTED = {"bas_version", "generated_at", "power_curve", "records", "best_climbs"}
@@ -121,6 +126,25 @@ def _rebuild_athlete_json(data: Path, handle: str | None = None) -> None:
             summaries = index_data.get("activities", [])
             if not summaries:
                 continue
+
+            # Apply sidecar edits so overrides (e.g. sub_sport: indoor) are visible
+            # to write_athlete_json without stripping best_efforts/best_climb_m.
+            edits_dir = user_dir / "edits"
+            if edits_dir.exists():
+                sidecars: dict[str, dict] = {}
+                for sc_path in edits_dir.glob("*.md"):
+                    try:
+                        fm, _ = parse_sidecar(sc_path)
+                        sidecars[sc_path.stem] = fm
+                    except Exception:
+                        pass
+                if sidecars:
+                    summaries = [
+                        _apply_sidecar_summary(s, sidecars[s["id"]])
+                        if s.get("id") in sidecars else s
+                        for s in summaries
+                    ]
+
             athlete_config: dict = {}
             athlete_path = user_dir / "athlete.json"
             if athlete_path.exists():
@@ -134,6 +158,68 @@ def _rebuild_athlete_json(data: Path, handle: str | None = None) -> None:
             console.print(f"  [yellow]{user_dir.name}[/yellow]: rebuild_athlete failed: {exc}")
 
 
+def _recompute_best_climbs(data: Path, handle: str | None = None) -> None:
+    """Recompute best_climb_m for all cycling activities from their stored timeseries.
+
+    Updates activities/*.json and index.json in-place.  Run this once after
+    upgrading the climb algorithm to fix values computed by the old code.
+    """
+    import json
+    from bincio.extract.metrics import _best_climb
+
+    targets = [data / handle] if handle else _user_dirs(data)
+    for user_dir in targets:
+        acts_dir = user_dir / "activities"
+        index_path = user_dir / "index.json"
+        if not acts_dir.exists() or not index_path.exists():
+            continue
+        try:
+            index_data = json.loads(index_path.read_text(encoding="utf-8"))
+        except Exception:
+            continue
+
+        updated = 0
+        for act_path in acts_dir.glob("*.json"):
+            if act_path.stem.endswith((".timeseries", ".geojson")):
+                continue
+            ts_path = acts_dir / f"{act_path.stem}.timeseries.json"
+            if not ts_path.exists():
+                continue
+            try:
+                detail = json.loads(act_path.read_text(encoding="utf-8"))
+                if detail.get("sport") != "cycling":
+                    continue
+                ts = json.loads(ts_path.read_text(encoding="utf-8"))
+                t_vals = ts.get("t", [])
+                e_vals = ts.get("elevation_m", [])
+                pairs = sorted(
+                    (t, e) for t, e in zip(t_vals, e_vals) if e is not None
+                )
+                if len(pairs) < 2:
+                    continue
+                new_val = _best_climb(pairs)
+                if new_val == detail.get("best_climb_m"):
+                    continue
+                detail["best_climb_m"] = new_val
+                act_path.write_text(
+                    json.dumps(detail, indent=2, ensure_ascii=False), encoding="utf-8"
+                )
+                act_id = act_path.stem
+                for s in index_data.get("activities", []):
+                    if s.get("id") == act_id:
+                        s["best_climb_m"] = new_val
+                        break
+                updated += 1
+            except Exception:
+                pass
+
+        if updated:
+            index_path.write_text(
+                json.dumps(index_data, indent=2, ensure_ascii=False), encoding="utf-8"
+            )
+        console.print(f"  [cyan]{user_dir.name}[/cyan]: {updated} climb(s) recomputed")
+
+
 def _write_root_manifest(data: Path) -> None:
     """Rewrite the root index.json shard manifest from current user dirs."""
     import json
@@ -217,6 +303,9 @@ def _link_data(site: Path, data: Path) -> None:
               help="(Multi-user) Incrementally re-merge one user's shard only.")
 @click.option("--no-build", "no_build", is_flag=True,
               help="Skip the Astro build step (just merge sidecars and update manifests).")
+@click.option("--recompute-climbs", "recompute_climbs", is_flag=True,
+              help="Recompute best_climb_m for all cycling activities from stored timeseries "
+                   "(run once after upgrading the climb algorithm).")
 def render(
     config_path: Optional[str],
     data_dir: Optional[str],
@@ -226,6 +315,7 @@ def render(
     deploy: Optional[str],
     handle: Optional[str],
     no_build: bool,
+    recompute_climbs: bool,
 ) -> None:
     """Build (or serve) the BincioActivity static site from a BAS data store."""
 
@@ -235,6 +325,10 @@ def render(
     console.print(f"Site:  [cyan]{site}[/cyan]")
     console.print(f"Data:  [cyan]{data}[/cyan]")
 
+    if recompute_climbs:
+        console.print("Recomputing best climbs from timeseries…")
+        _recompute_best_climbs(data, handle=handle)
+
     _merge_edits(data, handle=handle)
     _rebuild_athlete_json(data, handle=handle)
     _bake_tracks(data, handle=handle)