feat(logs): readable greppable per-agent transcript logs (agent-log.py)

The raw 'tmux pipe-pane' logs are TUI-escape soup (the 191MB builder log).
agent-log.py renders Claude's own JSONL transcript into a clean one-event-
per-line <agent>.clean.log — read-only on a file the agent writes anyway, so
zero agent slowdown and zero extra tokens. Resolves each agent's transcript
(disambiguating the shared project dir by kickoff signature; tracks restarts).
'follow-all' runs as the cc-ci-cleanlogs session, wired into launch.py start
so it comes up with the loops. render/tail subcommands for ad-hoc use.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

cc-ci-plan/launch.py

@@ -626,6 +626,17 @@ def start_watchdog():
         f"exec >>'{LOG_DIR}/watchdog.log' 2>&1; {env_prefix}python3 '{script}' watchdog"
     ])
 
+def start_cleanlogs():
+    """Maintain readable, greppable per-agent transcript logs (<agent>.clean.log) by tailing each
+    session's JSONL — costs nothing on the agents (read-only on a file claude writes anyway)."""
+    if session_alive("cc-ci-cleanlogs"):
+        log("cleanlogs already running")
+        return
+    log("starting cleanlogs (per-agent <agent>.clean.log)")
+    al = Path(__file__).resolve().parent / "agent-log.py"
+    subprocess.run(["tmux", "new-session", "-d", "-s", "cc-ci-cleanlogs", "-c", PLAN_DIR,
+                    f"python3 '{al}' follow-all"])
+
 # ── preflight ─────────────────────────────────────────────────────────────────
 
 def preflight():
@@ -686,6 +697,7 @@ def main():
         log(f"phases='{all_ids()}' (persisted to {_PHASES_FILE})")
         start_loops()
         start_watchdog()
+        start_cleanlogs()
         log(f"started at phase {phase_id(cur_idx())}.")
 
     elif cmd == "watchdog":