reextract: use venv bincio script, not uv, to spawn subprocess

uv is unreliable in systemd environments where PATH omits ~/.local/bin.
Use sys.executable's parent directory to find the venv's bincio script
directly — this always works since the server itself runs from the venv.

bincio/serve/server.py

@@ -631,21 +631,22 @@ async def admin_reextract_originals(
     Triggers a full rebuild on completion.
     """
     import asyncio
-    import shutil
     _require_admin(bincio_session)
     user_dir = _get_data_dir() / handle
     originals_dir = user_dir / "originals" / "strava"
     if not originals_dir.exists():
         raise HTTPException(404, f"No Strava originals directory for '{handle}'")
 
-    # Find the `uv` or `bincio` executable that launched us
-    uv_exe = shutil.which("uv") or "uv"
+    # Use the bincio script from the same venv bin dir as the running Python.
+    # This is reliable in systemd environments where PATH may not include uv.
+    import sys as _sys
+    bincio_exe = str(Path(_sys.executable).parent / "bincio")
     data_dir = str(_get_data_dir())
-    log.info("reextract[%s]: spawning subprocess via %s", handle, uv_exe)
+    log.info("reextract[%s]: spawning subprocess via %s", handle, bincio_exe)
 
     async def event_stream():
         proc = await asyncio.create_subprocess_exec(
-            uv_exe, "run", "bincio", "reextract-originals",
+            bincio_exe, "reextract-originals",
             "--data-dir", data_dir,
             "--handle", handle,
             stdout=asyncio.subprocess.PIPE,