Explore: personal GPS heatmap tab under Athlete page

- bincio/explore.py: bake_tracks() simplifies GPS coords (RDP ε=0.0001),
  strips to [lng,lat], groups by sport type, writes per-handle tracks.json
- bake-tracks CLI command; render CLI calls _bake_tracks() after each build;
  strava_zip runs it once at end of batch
- /api/me/tracks endpoint serves the baked file; wipe_user cleans it up
- Explore.svelte: MapLibre full-screen map with sidebar — type pills,
  year/month date filter, Lines / Heatmap (global or by-type) view modes
- AthleteView: Explore tab visible only to profile owner (checks __bincioMe)
- Base.astro: fullscreen prop + Planner nav link

bincio/serve/routers/me.py

@@ -7,7 +7,7 @@ from pathlib import Path
 from typing import Any
 
 from fastapi import APIRouter, Cookie, HTTPException, Request
-from fastapi.responses import JSONResponse
+from fastapi.responses import JSONResponse, Response
 
 from bincio.serve import deps, tasks
 from bincio.serve.db import (
@@ -43,7 +43,7 @@ def _wipe_user_activities(user_dir: Path) -> int:
         if d.exists():
             shutil.rmtree(d)
 
-    for name in ("index.json", "athlete.json", ".bincio_cache.json"):
+    for name in ("index.json", "athlete.json", ".bincio_cache.json", "tracks.json"):
         f = user_dir / name
         if f.exists():
             f.unlink()
@@ -52,6 +52,16 @@ def _wipe_user_activities(user_dir: Path) -> int:
     return deleted
 
 
+@router.get("/api/me/tracks")
+async def me_tracks(bincio_session: str | None = Cookie(default=None)) -> Response:
+    """Return the pre-baked tracks.json for the logged-in user (Explore page)."""
+    user = deps._require_user(bincio_session)
+    tracks_path = deps._get_data_dir() / user.handle / "tracks.json"
+    if not tracks_path.exists():
+        raise HTTPException(404, "Tracks not yet baked — upload an activity first")
+    return Response(content=tracks_path.read_bytes(), media_type="application/json")
+
+
 @router.get("/api/me/storage")
 async def me_storage(bincio_session: str | None = Cookie(default=None)) -> JSONResponse:
     """Return per-category disk usage for the logged-in user."""

bincio/serve/routers/uploads.py

@@ -487,6 +487,11 @@ async def upload_strava_zip(
                              user.handle, imported_count, error_count)
                     if any_imported:
                         merge_all(dd)
+                        try:
+                            from bincio.explore import bake_tracks
+                            bake_tracks(user.handle, deps._get_data_dir())
+                        except Exception as exc:
+                            log.warning("strava-zip[%s]: bake_tracks failed (non-fatal): %s", user.handle, exc)
                         tasks._trigger_rebuild(user.handle)
         except Exception as exc:
             log.error("strava-zip[%s]: fatal error: %s", user.handle, exc, exc_info=True)