feat: decision-log data layer for Decide mode (learning layer)

Storage + tools so Decide mode can learn instead of one-shot tie-breaking: log
the call Brian makes, resolve it later with the outcome, recall similar past calls
to ground new recommendations in his own track record.

- memory: decisions table + Decision dataclass + log/resolve/get/list/recall_decisions
  (embedding over situation+choice; embed failure never blocks a log)
- tools: log_decision / resolve_decision / recall_decisions handlers + specs
- tests: 9 covering roundtrip, resolve, open-only filter, similarity rank, tool layer

Data layer only — NOT wired into any mode's allow-list or the Decide card yet
(the prompt/taste part is left for Brian; see docs/DECISION_LOG.md). No behavior
changes until the tools are added to _DECIDE_TOOLS.

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

lyra/memory.py

@@ -115,6 +115,26 @@ CREATE TABLE IF NOT EXISTS ratings (
     note TEXT
 );
 CREATE INDEX IF NOT EXISTS idx_ratings_created ON ratings(created_at);
+
+-- Decisions Lyra helped Brian make (Decide mode's learning layer). Logged when the
+-- call is made; resolved later with how it actually turned out; recalled by semantic
+-- similarity so a new call can lean on how similar ones went. embedding covers the
+-- situation + choice. Resolved rows (with an outcome) are the signal worth recalling.
+CREATE TABLE IF NOT EXISTS decisions (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    created_at TEXT NOT NULL,
+    situation TEXT NOT NULL,    -- what was being decided
+    options TEXT,               -- the alternatives weighed (free text / newline list)
+    choice TEXT NOT NULL,       -- the call that was made
+    rationale TEXT,             -- why
+    confidence INTEGER,         -- 1-5, how sure at the time (nullable)
+    tags TEXT,                  -- domain: poker | life | build | ... (comma-separated)
+    embedding BLOB,
+    outcome TEXT,               -- filled in on resolve: what actually happened
+    outcome_rating INTEGER,     -- -1 bad / 0 mixed / +1 good (nullable until resolved)
+    resolved_at TEXT
+);
+CREATE INDEX IF NOT EXISTS idx_decisions_created ON decisions(created_at);
 """
 
 _conn: sqlite3.Connection | None = None
@@ -184,6 +204,26 @@ class Era:
     score: float | None = None
 
 
+@dataclass
+class Decision:
+    id: int
+    created_at: str
+    situation: str
+    choice: str
+    options: str | None = None
+    rationale: str | None = None
+    confidence: int | None = None
+    tags: str | None = None
+    outcome: str | None = None
+    outcome_rating: int | None = None
+    resolved_at: str | None = None
+    score: float | None = None
+
+    @property
+    def resolved(self) -> bool:
+        return self.resolved_at is not None
+
+
 def _to_blob(vec: list[float]) -> bytes:
     return np.asarray(vec, dtype=np.float32).tobytes()
 
@@ -645,6 +685,87 @@ def backfill_journal_embeddings(limit: int | None = None) -> int:
     return n
 
 
+# --- decisions (Decide mode's learning layer) ---------------------------------
+
+def _row_to_decision(r: sqlite3.Row) -> Decision:
+    return Decision(
+        id=r["id"], created_at=r["created_at"], situation=r["situation"],
+        choice=r["choice"], options=r["options"], rationale=r["rationale"],
+        confidence=r["confidence"], tags=r["tags"], outcome=r["outcome"],
+        outcome_rating=r["outcome_rating"], resolved_at=r["resolved_at"],
+    )
+
+
+def log_decision(situation: str, choice: str, options: str | None = None,
+                 rationale: str | None = None, confidence: int | None = None,
+                 tags: str | None = None) -> int:
+    """Record a decision Brian made. Embeds situation+choice so similar future calls
+    can recall it. Returns the new row id. Resolve it later with resolve_decision."""
+    now = datetime.now(timezone.utc).isoformat()
+    try:
+        [emb] = llm.embed([f"{situation}\nChose: {choice}"])
+        blob = _to_blob(emb)
+    except Exception:
+        blob = None  # never block logging a decision on the embedder being down
+    conn = _connection()
+    with conn:
+        cur = conn.execute(
+            "INSERT INTO decisions (created_at, situation, options, choice, rationale, "
+            "confidence, tags, embedding) VALUES (?, ?, ?, ?, ?, ?, ?, ?)",
+            (now, situation, options, choice, rationale, confidence, tags, blob),
+        )
+    return int(cur.lastrowid)
+
+
+def resolve_decision(decision_id: int, outcome: str, outcome_rating: int | None = None) -> bool:
+    """Record how a past decision turned out. Returns False if the id is unknown."""
+    now = datetime.now(timezone.utc).isoformat()
+    conn = _connection()
+    with conn:
+        cur = conn.execute(
+            "UPDATE decisions SET outcome = ?, outcome_rating = ?, resolved_at = ? WHERE id = ?",
+            (outcome, outcome_rating, now, decision_id),
+        )
+    return cur.rowcount > 0
+
+
+def get_decision(decision_id: int) -> Decision | None:
+    r = _connection().execute("SELECT * FROM decisions WHERE id = ?", (decision_id,)).fetchone()
+    return _row_to_decision(r) if r else None
+
+
+def list_decisions(limit: int = 20, open_only: bool = False) -> list[Decision]:
+    """Recent decisions, newest first. open_only -> only those not yet resolved."""
+    sql = "SELECT * FROM decisions"
+    if open_only:
+        sql += " WHERE resolved_at IS NULL"
+    sql += " ORDER BY created_at DESC LIMIT ?"
+    rows = _connection().execute(sql, (limit,)).fetchall()
+    return [_row_to_decision(r) for r in rows]
+
+
+def recall_decisions(query: str, k: int = 5) -> list[Decision]:
+    """Top-k past decisions semantically similar to `query`, each with a `score` — so a
+    new call can lean on how similar ones went. Resolved rows carry the real signal."""
+    [q_vec] = llm.embed([query])
+    q = np.asarray(q_vec, dtype=np.float32)
+    rows = _connection().execute(
+        "SELECT * FROM decisions WHERE embedding IS NOT NULL"
+    ).fetchall()
+    if not rows:
+        return []
+    matrix = np.stack([_from_blob(r["embedding"]) for r in rows])
+    norms = np.linalg.norm(matrix, axis=1)
+    scores = (matrix @ q) / (norms * np.linalg.norm(q) + 1e-9)
+    top_idx = np.argsort(scores)[::-1][:k]
+    out = []
+    for i in top_idx:
+        d = _row_to_decision(rows[i])
+        d.score = float(scores[i])
+        out.append(d)
+    return out
+
+
 def get_setting(key: str, default: str | None = None) -> str | None:
     """A runtime setting value (UI-tunable), or `default` if unset."""
     r = _connection().execute("SELECT value FROM settings WHERE key = ?", (key,)).fetchone()