fix(runtime): improve local service reliability

Close SQLite handles safely on Windows, clean orphaned vectors, normalize Ollama endpoints, and surface model errors without leaking reasoning tags.

Co-authored-by: Cursor <cursoragent@cursor.com>

bin/sync.py

@@ -18,6 +18,7 @@ bin/db-compare.sh could never work there.
 A fresh machine clones first (git clone <repo> nexus-core), then runs this.
 """
 import argparse
+import contextlib
 import os
 import shutil
 import sqlite3
@@ -125,7 +126,7 @@ def dump_db() -> bool:
     if not DB.exists():
         return False
     try:
-        with sqlite3.connect(f"file:{DB}?mode=ro", uri=True) as conn:
+        with contextlib.closing(sqlite3.connect(f"file:{DB}?mode=ro", uri=True)) as conn:
             DB_SQL.write_text("\n".join(conn.iterdump()) + "\n", encoding="utf-8")
     except sqlite3.Error as exc:
         print(f"Warning: could not dump {DB} ({exc}) - DB not captured")
@@ -171,9 +172,12 @@ def compare(db: Path = DB, dump: Path = DB_SQL) -> str:
     if not db.exists():
         return "no-live"
     try:
-        with sqlite3.connect(f"file:{db}?mode=ro", uri=True) as live_conn:
+        # closing(), not sqlite3's context manager: that one commits without
+        # closing, and restore_db() unlinks the DB right after calling this -
+        # Windows fails that unlink while any handle is still open.
+        with contextlib.closing(sqlite3.connect(f"file:{db}?mode=ro", uri=True)) as live_conn:
             live = _state(live_conn)
-        with sqlite3.connect(":memory:") as dump_conn:
+        with contextlib.closing(sqlite3.connect(":memory:")) as dump_conn:
             dump_conn.executescript(dump.read_text(encoding="utf-8"))
             backup = _state(dump_conn)
     except (sqlite3.Error, OSError):
@@ -216,7 +220,7 @@ def restore_db() -> None:
     for suffix in ("", "-wal", "-shm"):
         Path(str(DB) + suffix).unlink(missing_ok=True)
     try:
-        with sqlite3.connect(DB) as conn:
+        with contextlib.closing(sqlite3.connect(DB)) as conn, conn:
             conn.executescript(DB_SQL.read_text(encoding="utf-8"))
         print("Memory DB restored (conversations + history + facts).")
     except sqlite3.Error as exc: