feat: full-fidelity conversation export (chat + tool calls)

Chat only ever lived in SQLite's `exchanges` table (what was *said*); tool
calls were transient — logged to the in-memory ring buffer and gone at
end-of-turn. This adds a persistent record of what Lyra *did* and exports the
two merged into one transcript.

- memory: new `tool_events` table + `add_tool_event`/`tool_events` accessors;
  `delete_session` cascades to it.
- chat: persist each tool call (name/args/result) right where it fires, in both
  the non-stream and stream paths. Move the user `remember` to just after
  assembly so its timestamp precedes mid-turn tool events — keeps the export in
  true chronological order (and records when the message actually arrived).
- transcript: new module renders a session as Markdown (Brian/Lyra speech with
  ⚙ tool-call lines interleaved) or JSON (machine-readable event stream).
- server: GET /sessions/{id}/export?format=md|json (attachment download).
- ui: ⬇ Export button by the session selector (Markdown or JSON).

Doubles as the receipt for "did the tool actually fire?" — the thing that was
invisible when she'd reply about a hand without logging it.

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

lyra/memory.py

@@ -29,6 +29,21 @@ CREATE TABLE IF NOT EXISTS exchanges (
 );
 CREATE INDEX IF NOT EXISTS idx_session_created ON exchanges(session_id, created_at);
 
+-- Lyra's actions within a chat: one row per tool call she runs mid-turn. The
+-- exchanges table only holds what was *said* (user/assistant text); this holds
+-- what she *did* (record_hand, log_stack, ...) so a full transcript export can
+-- interleave speech and actions, and so "did the tool actually fire?" is
+-- answerable after the fact instead of only from ephemeral logs.
+CREATE TABLE IF NOT EXISTS tool_events (
+    id INTEGER PRIMARY KEY AUTOINCREMENT,
+    session_id TEXT NOT NULL,
+    tool TEXT NOT NULL,
+    args TEXT,                 -- JSON of the call arguments
+    result TEXT,               -- the tool's returned string
+    created_at TEXT NOT NULL
+);
+CREATE INDEX IF NOT EXISTS idx_tool_events_session ON tool_events(session_id, created_at);
+
 CREATE TABLE IF NOT EXISTS sessions (
     id TEXT PRIMARY KEY,
     name TEXT,
@@ -313,6 +328,40 @@ def history(session_id: str) -> list[Exchange]:
     ]
 
 
+def add_tool_event(session_id: str, tool: str, args, result: str) -> int:
+    """Record one tool call Lyra ran in a chat turn. `args` is JSON-serialized
+    (a dict or already-JSON string); `result` is the tool's returned string."""
+    args_json = args if isinstance(args, str) else json.dumps(args, default=str)
+    now = datetime.now(timezone.utc).isoformat()
+    conn = _connection()
+    with conn:
+        cur = conn.execute(
+            "INSERT INTO tool_events (session_id, tool, args, result, created_at) "
+            "VALUES (?, ?, ?, ?, ?)",
+            (session_id, tool, args_json, result, now),
+        )
+    return int(cur.lastrowid)
+
+
+def tool_events(session_id: str) -> list[dict]:
+    """All tool calls for a session, oldest first. args is parsed back to an object."""
+    conn = _connection()
+    rows = conn.execute(
+        "SELECT id, session_id, tool, args, result, created_at FROM tool_events "
+        "WHERE session_id = ? ORDER BY id ASC",
+        (session_id,),
+    ).fetchall()
+    out = []
+    for r in rows:
+        d = dict(r)
+        try:
+            d["args"] = json.loads(d["args"]) if d["args"] else {}
+        except (TypeError, ValueError):
+            pass  # leave as the raw string if it wasn't JSON
+        out.append(d)
+    return out
+
+
 def delete_session(session_id: str) -> None:
     """Remove a session and all its exchanges."""
     conn = _connection()
@@ -320,6 +369,7 @@ def delete_session(session_id: str) -> None:
         conn.execute("DELETE FROM exchanges WHERE session_id = ?", (session_id,))
         conn.execute("DELETE FROM sessions WHERE id = ?", (session_id,))
         conn.execute("DELETE FROM summaries WHERE session_id = ?", (session_id,))
+        conn.execute("DELETE FROM tool_events WHERE session_id = ?", (session_id,))
 
 
 def recall(query: str, k: int = 5, session_id: str | None = None) -> list[Exchange]: