M1-T04: converge startup chain onto the single app DB

run_all_migrations() now adopts/initializes only the app DB and returns
{'app': ...}. app/main.py drops the location/poo readiness checks
(ensure_location_db_ready / ensure_poo_db_ready) and their imports;
ensure_runtime_dirs only provisions the app DB path; lifespan still
fail-closes on a missing/unmanaged app DB. Delete the retired
location/poo adopt scripts and the alembic_location / alembic_poo
chains. Update tests to single-DB expectations and drop the obsolete
location/poo adoption + readiness tests.

pytest 95 passed; ruff clean (pre-existing only); a fresh app DB
initialized via scripts.run_migrations contains location + poo_records.

tests/test_ticktick.py

@@ -209,9 +209,6 @@ def test_create_task_posts_expected_payload(monkeypatch: pytest.MonkeyPatch) ->
 
 
 def test_homeassistant_publish_creates_ticktick_action_task(
-    test_database_urls,
-    ready_location_database,
-    ready_poo_database,
     auth_database,
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
@@ -255,9 +252,6 @@ def test_homeassistant_publish_creates_ticktick_action_task(
 
 
 def test_ticktick_auth_start_redirects_authenticated_user(
-    test_database_urls,
-    ready_location_database,
-    ready_poo_database,
     auth_database,
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
@@ -291,9 +285,6 @@ def test_ticktick_auth_start_redirects_authenticated_user(
 
 
 def test_ticktick_auth_callback_persists_token(
-    test_database_urls,
-    ready_location_database,
-    ready_poo_database,
     auth_database,
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
@@ -318,7 +309,7 @@ def test_ticktick_auth_callback_persists_token(
     assert response.status_code == 303
     assert response.headers["location"] == "/config?ticktick_oauth=success"
 
-    conn = sqlite3.connect(test_database_urls["app_path"])
+    conn = sqlite3.connect(auth_database["app_path"])
     try:
         row = conn.execute(
             "SELECT value FROM app_config WHERE key = ?",
@@ -332,9 +323,6 @@ def test_ticktick_auth_callback_persists_token(
 
 
 def test_ticktick_auth_callback_redirects_on_invalid_state(
-    test_database_urls,
-    ready_location_database,
-    ready_poo_database,
     auth_database,
     monkeypatch: pytest.MonkeyPatch,
 ) -> None:
@@ -356,9 +344,6 @@ def test_ticktick_auth_callback_redirects_on_invalid_state(
 
 
 def test_ticktick_auth_callback_redirects_when_token_exchange_fails(
-    test_database_urls,
-    ready_location_database,
-    ready_poo_database,
     auth_database,
     monkeypatch: pytest.MonkeyPatch,
 ) -> None: