supervisor: fix 3-day progress-gate deadlock (2026-08-07 run)

Root cause chain, all confirmed on the live system:
1. _run_pids() substring-matched the WHOLE cmdline for the session name. An agent's
   kickoff PROMPT is an argv element, and the supervisor's prompt text contains the
   literal 'cc-ci-upgrader' — so the supervisor's OWN billing-hung agent matched as a
   live upgrader run. Now matches FLAG VALUES only (--title <SESSION> / -s <sid>).
2. The gate treated 'a live proc exists' as progress. A provider-walled run keeps its
   process alive and SPINNING while emitting nothing (verified: 3 days, zero session
   output, still burning CPU). Progress now REQUIRES the session tree to have advanced
   within STALL_MIN; a live-but-idle proc is explicitly logged as stalled.
Result was ~60 consecutive false 'run progressing — leaving it' no-ops while the weekly
run sat unfinished and unreported.

Billing-walled runs are REPORTED, never killed (operator policy 2026-08-10): they may
resume when the wall lifts and their context is the run's state. New _billing_blocked()
detects the wall from the log tail and the gate surfaces
'run BLOCKED on a provider billing/usage wall — NOT killing; operator action required'.

Verified live: _run_pids no longer matches the hung Aug-7 supervisor (1497561) while
still matching the real finisher; gate now reasons 'session advanced Nm ago'.

cc-ci-plan/launch-upgrader.py

@@ -417,25 +417,55 @@ def _limit_retry_after():
         return 0
 
 def _run_pids(sid=None):
-    """PIDs of live `opencode run` procs for THIS session (via /proc scan — never matches self)."""
+    """PIDs of live `opencode run` procs for THIS session (via /proc scan — never matches self).
+
+    Matches on FLAG VALUES (`--title <SESSION>` / `-s|--session <sid>`), never a substring of the
+    whole cmdline. The substring form caused the 2026-08-07 three-day deadlock: an agent's kickoff
+    PROMPT is passed as an argv element, and the supervisor's prompt text contains the literal
+    "cc-ci-upgrader", so the supervisor's own (billing-hung) agent matched as a live upgrader run —
+    the hourly gate then read its own corpse as "run progressing" and no-opped ~60 times."""
     me, out = os.getpid(), []
     for p in os.listdir("/proc"):
         if not p.isdigit() or int(p) == me:
             continue
         try:
-            cl = open(f"/proc/{p}/cmdline", "rb").read().split(b"\0")
+            cl = [c for c in open(f"/proc/{p}/cmdline", "rb").read().split(b"\0") if c]
         except Exception:
             continue
-        joined = b" ".join(cl)
-        if not (b"opencode" in joined and b"run" in cl and b"--attach" in cl):
+        if not cl or b"opencode" not in cl[0] or b"run" not in cl or b"--attach" not in cl:
             continue
-        # Scope to THIS managed session only: a fresh run carries `--title <SESSION>`, a resumed
-        # run carries `-s <sid>`. Without this, the report watchdog would kill the idle upgrader
-        # run (and vice-versa) since both are `opencode run … --attach`.
-        if SESSION.encode() in joined or (sid and sid.encode() in joined):
+
+        def _flag(names):
+            for i, a in enumerate(cl[:-1]):
+                if a in names:
+                    return cl[i + 1]
+            return None
+
+        title = _flag((b"--title",))
+        s_val = _flag((b"-s", b"--session"))
+        if title == SESSION.encode() or (sid and s_val == sid.encode()):
             out.append(int(p))
     return out
 
+
+def _billing_blocked(window_bytes=4000):
+    """True when the tail of this run's log shows a provider billing/usage wall.
+
+    Such a process must NEVER be killed: it may resume when the wall lifts, and killing it can
+    lose in-flight work. It is also NOT progress — it can spin for days emitting nothing (observed
+    2026-08-07..10), so the gate reports it as BLOCKED and leaves recovery to the operator."""
+    try:
+        with open(LOG_FILE, "rb") as f:
+            f.seek(0, os.SEEK_END)
+            f.seek(max(0, f.tell() - window_bytes))
+            tail = f.read().decode(errors="replace").lower()
+    except OSError:
+        return False
+    return any(
+        s in tail
+        for s in ("spending limit", "insufficient balance", "usage limit", "usagelimiterror")
+    )
+
 def _completed():
     # Done only when the MODEL signs off with DONE_MARKER as its FINAL word: the marker in the LAST
     # assistant TEXT (prose) message. This guards THREE false-positives that each abandoned a run: