feat: surface task execution progress across Host Agent and Cloud

Host Agent now persists step-level execution detail locally (via a real
TaskMetadataStore/Timeline wired into TaskRunner) and reports a bounded
in-progress snapshot piggybacked on lease renewal. Cloud persists that
snapshot per active assignment and exposes it through the existing task
list/detail query path; Cloud Console renders it as a live badge. Host
Agent's local console gains authenticated, read-only task list and
detail/timeline pages (same-origin, server-rendered) with inlined
screenshots.

Also fixes a pre-existing gap in the shared Timeline: the actual
per-step LLM prompt is now recorded instead of the task goal, benefiting
both Runtime and Host Agent consoles. When a host uses the cloud planner
transport, each decide call's prompt and resulting tool decision are
durably logged in a new planner_decision_log table (with bounded
retention) and browsable from Cloud Console; direct-transport hosts
explicitly surface a "not reported" state.

Includes Alembic migrations 0008 (progress columns on scheduled_tasks)
and 0009 (planner_decision_log), bounded Host-Agent-local retention,
dual-backend repository parity, and Vitest + pytest coverage. Task 6.5
(manual end-to-end device verification) remains.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

storage/task_metadata.py

@@ -73,6 +73,21 @@ class TaskMetadataStore:
             ).fetchall()
         return [dict(row) for row in rows]
 
+    def list_task_ids(self) -> list[str]:
+        with self._connect() as connection:
+            rows = connection.execute(
+                "select id from tasks order by created_at desc"
+            ).fetchall()
+        return [row["id"] for row in rows]
+
+    def delete_task(self, task_id: str) -> None:
+        """Delete a task row. No-op if the task does not exist."""
+        with self._connect() as connection:
+            connection.execute(
+                "delete from tasks where id = ?",
+                (task_id,),
+            )
+
     def _ensure_schema(self) -> None:
         with self._connect() as connection:
             connection.execute(
@@ -94,4 +109,3 @@ class TaskMetadataStore:
         connection = sqlite3.connect(self.db_path)
         connection.row_factory = sqlite3.Row
         return connection
-