Warn that Auto falls back to prompting when unavailable

Claude Code starts in its prompting mode when auto isn't available for the
session's model or backend, so a headless Auto task can still stall. Say so
in the task editor, the task runner comment, and HOW-TO-USE.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

container/triple-c-task-runner

@@ -61,9 +61,10 @@ TASK_TYPE=$(jq -r '.type' "$TASK_FILE")
 # project's permission setting. Keep this mapping in sync with
 # PermissionMode::cli_args() in app/src-tauri/src/models/project.rs.
 # NOTE: headless `claude -p` runs cannot answer a permission prompt, so any
-# mode other than "bypass" or "auto" means the task may stop early when Claude
-# Code asks for permission. In "auto", actions the classifier blocks are
-# denied rather than prompted, so the run continues without them. Unset or unrecognized values pass no flag (Claude's default).
+# mode other than "bypass" means the task may stop early when Claude Code asks
+# for permission. In "auto", classifier-blocked actions are denied instead of
+# prompted, but if auto mode is unavailable for the session's model/backend,
+# Claude Code falls back to prompting and the same stall applies. Unset or unrecognized values pass no flag (Claude's default).
 PERMISSION_ARGS=()
 case "${TRIPLE_C_PERMISSION_MODE:-}" in
     plan)        PERMISSION_ARGS=(--permission-mode plan) ;;