feat: behind-the-scenes 👍/👎 rating system (fine-tune data collection)

Brian can rate Lyra's outputs as he uses her; each rating is stored as a
(context, content, rating) triple — the shape a future fine-tune / preference
dataset wants, collected passively during real use.

- memory: ratings table + add_rating (upsert: one row per item, re-rating
  replaces), list_ratings, rating_counts
- server: POST /rate, GET /ratings/counts, GET /ratings/export (JSONL download)
- chat UI: subtle 👍/👎 on each assistant reply, captures the prompting message
  as context
- journal/reflection UI: 👍/👎 on each thought
- tests: counts + upsert-replace behavior

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

lyra/memory.py

@@ -92,6 +92,21 @@ CREATE TABLE IF NOT EXISTS journal (
     source TEXT
 );
 CREATE INDEX IF NOT EXISTS idx_journal_created ON journal(created_at);
+
+-- Brian's behind-the-scenes feedback on Lyra's outputs (chat replies, reflections,
+-- journal/metacognition). Stored as (context, content, rating) — the shape a future
+-- fine-tune / preference dataset wants. One row per rated item (re-rating updates it).
+CREATE TABLE IF NOT EXISTS ratings (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    created_at TEXT NOT NULL,
+    kind TEXT NOT NULL,        -- chat | reflection | metacognition | journal
+    rating INTEGER NOT NULL,   -- +1 (good / want more) or -1 (off / want less)
+    content TEXT NOT NULL,     -- the rated output
+    context TEXT,              -- what prompted it (e.g. the user message for a chat reply)
+    ref TEXT,                  -- optional source id (journal id, session id, ...)
+    note TEXT
+);
+CREATE INDEX IF NOT EXISTS idx_ratings_created ON ratings(created_at);
 """
 
 _conn: sqlite3.Connection | None = None
@@ -542,6 +557,41 @@ def add_journal_entry(kind: str, content: str, source: str | None = None) -> int
     return int(cur.lastrowid)
 
 
+def add_rating(kind: str, rating: int, content: str, context: str | None = None,
+               ref: str | None = None, note: str | None = None) -> int:
+    """Record (or replace) Brian's feedback on one Lyra output. One row per item:
+    re-rating the same content updates it. Returns row id."""
+    now = datetime.now(timezone.utc).isoformat()
+    conn = _connection()
+    with conn:
+        conn.execute("DELETE FROM ratings WHERE kind = ? AND content = ?", (kind, content))
+        cur = conn.execute(
+            "INSERT INTO ratings (created_at, kind, rating, content, context, ref, note) "
+            "VALUES (?, ?, ?, ?, ?, ?, ?)",
+            (now, kind, 1 if rating >= 0 else -1, content, context,
+             str(ref) if ref is not None else None, note),
+        )
+    return int(cur.lastrowid)
+
+
+def list_ratings(limit: int | None = None) -> list[dict]:
+    conn = _connection()
+    sql = "SELECT id, created_at, kind, rating, content, context, ref, note FROM ratings ORDER BY id DESC"
+    if limit is not None:
+        sql += f" LIMIT {int(limit)}"
+    return [dict(r) for r in conn.execute(sql).fetchall()]
+
+
+def rating_counts() -> dict:
+    conn = _connection()
+    r = conn.execute(
+        "SELECT COUNT(*) AS total, "
+        "COALESCE(SUM(CASE WHEN rating > 0 THEN 1 ELSE 0 END), 0) AS up, "
+        "COALESCE(SUM(CASE WHEN rating < 0 THEN 1 ELSE 0 END), 0) AS down FROM ratings"
+    ).fetchone()
+    return {"total": r["total"], "up": r["up"], "down": r["down"]}
+
+
 def list_journal(limit: int | None = None, kinds: tuple[str, ...] | None = None) -> list[dict]:
     """Journal entries, newest first. Optionally filter by kind."""
     conn = _connection()