Docs: document MOT/insurance renewals, due-soon state, new settings

- README: feature list now covers renewal tracking, the due-soon service
  state, and the full event-type set.
- AGENTS: add the three hint settings, compute_renewal_due, favicon.svg,
  and test_renewals.py to the layouts.

AGENTS.md

@@ -5,8 +5,10 @@ Guidance for working in this repo.
 ## What this is
 
 `bike-admin` is a small single-user web app for logging bike service/repair
-"events" (type, date, mileage, cost, notes) and seeing a per-bike **service-due**
-hint derived from the newest mileage and the most recent `service` event.
+"events" (type, date, mileage, cost, notes) and seeing per-bike hints: a
+**service-due** status derived from the newest mileage and the most recent
+`service` event, plus **MOT / insurance renewal** statuses derived from the most
+recent `mot` / `insurance` events.
 
 Stack: FastAPI (ASGI) + stdlib `sqlite3` (WAL) + Jinja2 + HTMX. Server-rendered
 pages with HTMX partial swaps on the bike page. No build step. Dependencies via
@@ -38,19 +40,24 @@ All settings come from env vars (or a `.env` file) via `pydantic-settings`,
   behind a TLS reverse proxy over HTTPS).
 - `BIKE_ADMIN_BIND_HOST` / `BIND_PORT` — bind address/port.
 - `BIKE_ADMIN_DATA_DIR` — directory for the SQLite file (`bike_admin.db`).
+- Hints: `BIKE_ADMIN_SERVICE_DUE_SOON_MILES` (service "book soon" lead time,
+  default 200), `BIKE_ADMIN_RENEWAL_DUE_SOON_DAYS` (MOT/insurance "due soon"
+  lead time, default 60), `BIKE_ADMIN_RENEWAL_MONTHS` (MOT/insurance validity,
+  default 12).
 
 ## Architecture / layout
 
 - `app/config.py`  – `Settings` (pydantic-settings) + `get_settings()` (cached).
 - `app/db.py`      – SQLite schema + typed DAO helpers + `get_conn()` context manager.
 - `app/security.py`– Argon2 password hashing, DB session tokens, CSRF, login throttle.
-- `app/services.py`– Business logic: `compute_service_due`, `summarize_bike`, `all_summaries`.
+- `app/services.py`– Business logic: `compute_service_due`, `compute_renewal_due`,
+  `summarize_bike`, `all_summaries`.
 - `app/main.py`    – App factory, lifespan (schema init + user seed), security-header
   middleware, all routes, HTMX partial rendering.
 - `app/templates/` – Jinja2 templates (login, dashboard, bike detail, event partial).
-- `app/static/`    – `main.css` and vendored `htmx.min.js`.
+- `app/static/`    – `main.css`, `favicon.svg`, and vendored `htmx.min.js`.
 - `tests/`         – `conftest.py` (Client helper + temp-data-dir env) and per-area
-  tests.
+  tests (`test_auth`, `test_due`, `test_renewals`, `test_events`, `test_security`).
 
 ## Conventions & gotchas