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/device-host-agent/host_agent/status.py

@@ -6,6 +6,7 @@ from datetime import UTC, datetime
 from typing import TYPE_CHECKING, Any
 
 from cloud.internal_api.models import AssignmentModel
+from host_agent.progress import TaskProgressSnapshot
 
 if TYPE_CHECKING:
     from collections.abc import Callable
@@ -34,6 +35,7 @@ class AgentStatusTracker:
         self._current_assignment: _CurrentAssignment | None = None
         self._last_heartbeat: _LastHeartbeat | None = None
         self._host_policy: dict[str, Any] | None = None
+        self._latest_progress: TaskProgressSnapshot | None = None
 
     def mark_assignment_started(self, assignment: AssignmentModel) -> None:
         with self._lock:
@@ -48,6 +50,11 @@ class AgentStatusTracker:
     def mark_assignment_finished(self) -> None:
         with self._lock:
             self._current_assignment = None
+            self._latest_progress = None
+
+    def set_latest_progress(self, snapshot: TaskProgressSnapshot | None) -> None:
+        with self._lock:
+            self._latest_progress = snapshot
 
     def mark_heartbeat(self, *, ok: bool, device_count: int) -> None:
         with self._lock:
@@ -74,6 +81,7 @@ class AgentStatusTracker:
         with self._lock:
             current_assignment = self._current_assignment
             last_heartbeat = self._last_heartbeat
+            progress = self._latest_progress
         return {
             "current_assignment": (
                 {
@@ -96,4 +104,14 @@ class AgentStatusTracker:
                 else None
             ),
             "host_policy": self._host_policy.copy() if self._host_policy else None,
+            "progress": (
+                {
+                    "step_index": progress.step_index,
+                    "step_status": progress.step_status,
+                    "summary": progress.summary,
+                    "updated_at": progress.updated_at.isoformat(),
+                }
+                if progress is not None
+                else None
+            ),
         }