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>

tests/test_cloud_migrations.py

@@ -195,6 +195,57 @@ def test_schema_readiness_requires_head_revision(tmp_path) -> None:
     require_current_schema(database_url)
 
 
+def test_planner_decision_log_migration_upgrades_and_downgrades(tmp_path) -> None:
+    database_url = _database_url(tmp_path)
+
+    upgrade_database(database_url, "0008_task_progress_columns")
+    engine = create_engine(database_url)
+    try:
+        inspector = inspect(engine)
+        assert "planner_decision_log" not in inspector.get_table_names()
+    finally:
+        engine.dispose()
+
+    upgrade_database(database_url)
+
+    engine = create_engine(database_url)
+    try:
+        inspector = inspect(engine)
+        assert "planner_decision_log" in inspector.get_table_names()
+        columns = {col["name"] for col in inspector.get_columns("planner_decision_log")}
+        assert {
+            "id",
+            "host_id",
+            "task_id",
+            "attempt",
+            "step_index",
+            "system_prompt",
+            "user_prompt",
+            "tool_name",
+            "arguments_json",
+            "created_at",
+        } <= columns
+        index_names = {
+            idx["name"] for idx in inspector.get_indexes("planner_decision_log")
+        }
+        assert {
+            "ix_planner_decision_log_task_attempt",
+            "ix_planner_decision_log_host_created",
+        } <= index_names
+        assert current_revision(database_url) == HEAD_REVISION
+    finally:
+        engine.dispose()
+
+    downgrade_database(database_url, "0008_task_progress_columns")
+    engine = create_engine(database_url)
+    try:
+        inspector = inspect(engine)
+        assert "planner_decision_log" not in inspector.get_table_names()
+        assert current_revision(database_url) == "0008_task_progress_columns"
+    finally:
+        engine.dispose()
+
+
 def _create_legacy_schema(connection) -> None:
     connection.exec_driver_sql(
         "create table host_registrations ("