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>

apps/cloud-api/cloud_api/app.py

@@ -187,6 +187,19 @@ def create_app(
                     ),
                     name="cloud-lease-reaper",
                 ),
+                asyncio.create_task(
+                    _run_planner_decision_log_pruner_loop(
+                        services,
+                        stop_workers,
+                        interval_seconds=(
+                            control_config.planner_decision_log_prune_interval_seconds
+                        ),
+                        retention_days=(
+                            control_config.planner_decision_log_retention_days
+                        ),
+                    ),
+                    name="cloud-planner-decision-log-pruner",
+                ),
             ]
             app.state.worker_tasks = tuple(worker_tasks)
             app.state.startup_complete = True
@@ -442,3 +455,28 @@ async def _wait_for_stop(stop: asyncio.Event, interval_seconds: float) -> bool:
     except TimeoutError:
         return False
     return True
+
+
+async def _run_planner_decision_log_pruner_loop(
+    services: CloudApplicationServices,
+    stop: asyncio.Event,
+    *,
+    interval_seconds: float,
+    retention_days: int,
+) -> None:
+    while not stop.is_set():
+        correlation_token = bind_correlation_id(new_correlation_id())
+        try:
+            services.repository.prune_planner_decision_log(
+                now=utc_now(),
+                prune_after_terminal_seconds=retention_days * 86_400,
+            )
+        except Exception:
+            logger.exception(
+                "planner decision log prune failed",
+                extra={"worker": "planner_decision_log_pruner"},
+            )
+        finally:
+            reset_correlation_id(correlation_token)
+        if await _wait_for_stop(stop, interval_seconds):
+            return