Say when a scheduled task is running

A run is detached — cron has no terminal, and the app fires it as a detached
exec — so triggering one and watching the log was indistinguishable from
triggering one that died. Worse, `claude -p` writes its answer in a single
burst at the end, so a healthy run shows nothing but its log header for as
long as it is thinking. The honest reading of the old UI was "it stalled".

triple-c-task-runner now publishes a state file per run (pid, start time, log
path) and removes it from an EXIT trap. flock remains what actually prevents
overlapping runs; this is purely observability, so every reader verifies the
pid rather than trusting the file — a container stopped mid-run cannot fire a
trap, and a task stuck on "running" forever would be a worse lie than no
indicator at all. Stale files are cleared on read.

On top of that:

- `list` grows a status column: "running 4m12s" or "idle".
- `status [--id] [--watch]` answers "is it still going?" directly, with
  elapsed time and the tail of the log when there is any output yet.
- `run` streams the log instead of blocking silently, and refuses to start a
  task that is already running.
- The Automation tab marks a running task, disables its Run now button, and
  polls while anything is in flight — including the second or two between
  firing a run and the runner registering it, which is the exact window that
  used to read as dead.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

container/triple-c-task-runner

@@ -9,6 +9,7 @@ SCHEDULER_DIR="${HOME}/.claude/scheduler"
 TASKS_DIR="${SCHEDULER_DIR}/tasks"
 LOGS_DIR="${SCHEDULER_DIR}/logs"
 NOTIFICATIONS_DIR="${SCHEDULER_DIR}/notifications"
+RUNNING_DIR="${SCHEDULER_DIR}/running"
 ENV_FILE="${SCHEDULER_DIR}/.env"
 
 TASK_ID="${1:-}"
@@ -77,6 +78,27 @@ mkdir -p "$TASK_LOG_DIR"
 TIMESTAMP=$(date +"%Y%m%d-%H%M%S")
 LOG_FILE="${TASK_LOG_DIR}/${TIMESTAMP}.log"
 
+# ── Publish run state ───────────────────────────────────────────────────────
+# A scheduled run is detached — cron has no terminal, and the app fires it as a
+# detached exec — so without this there is no way to tell a task that is still
+# thinking from one that died, and a long run reads as a stall. `list`, `status`
+# and the app's Automation tab all read this file.
+#
+# flock above is what actually prevents overlapping runs; this is purely an
+# observability record, which is why readers verify the pid rather than trust
+# the file. The EXIT trap covers the crash paths (OOM, container stop, SIGTERM)
+# that would otherwise leave a task looking like it had been running for days.
+mkdir -p "$RUNNING_DIR"
+RUN_STATE="${RUNNING_DIR}/${TASK_ID}.json"
+trap 'rm -f "$RUN_STATE"' EXIT
+jq -n \
+    --arg pid "$$" \
+    --arg started "$(date +%s)" \
+    --arg log "$LOG_FILE" \
+    --arg name "$TASK_NAME" \
+    '{pid: ($pid | tonumber), started_epoch: ($started | tonumber), log: $log, name: $name}' \
+    > "$RUN_STATE"
+
 # ── Execute Claude agent ────────────────────────────────────────────────────
 {
     echo "=== Task: $TASK_NAME ($TASK_ID) ==="