Add per-board layout templates and a pre-sleep lead time

Two Vestaboard features, both configurable from the board editor without
rebuilding the app:

- Custom board layouts. An "Advanced" section takes a sandboxed Jinja
  template that replaces the built-in layout: one rendered line per board
  row, `LEFT | RIGHT` splits a row, everything else centers. `{% if %}`
  works, so the bottom row can show the delay when there is one and the
  next ship's name when there isn't. trim_blocks/lstrip_blocks keep a
  conditional on its own line from emitting a blank row; a failing template
  shows TEMPLATE ERROR on the preview instead of pushing a blank board.
  Example templates are per-model so a 6-row flagship layout doesn't lose
  its conditional line when truncated onto a 3-row Note. Full variable list
  documented in-UI and in the README.

- Pre-sleep lead time. The sleep message now goes out quiet.sleep_lead_min
  minutes (default 3) before the quiet window's start, and ferry pushes stop
  at that same early moment. A board's own Quiet Hours drop incoming
  messages and aren't reachable from the Read/Write API, so pushing at the
  exact start can leave the ferry layout up all night. The board editor
  links to web2.vestaboard.com for that device-side setting.

Verified against the live data dir via a wip build driven through the real
/api/vestaboard preview endpoint (delay -> "DELAYED 11:30A", no delay ->
next vessel name) on both Note and flagship. 24 tests pass.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: cdibona

CLAUDE.md

@@ -17,18 +17,19 @@ TRMNL e-ink devices and Vestaboard split-flap displays. Public, MIT,
 
 ## Layout
 
-Almost everything is `web/app.py` (~3.3k lines), in this order:
+Almost everything is `web/app.py` (~3.5k lines), in this order:
 
 | Lines (approx) | What |
 |---|---|
 | 1–310 | config, `APP_VERSION`, timezone helpers, Discord notify |
-| 313–520 | `TRMNL_MK_*` Liquid markup constants, one per device layout |
-| 520–1630 | the control-panel HTML/CSS/JS, inline as Python strings |
-| 1634–1970 | WSDOT fetch, route/direction logic, delay parsing |
-| 1973–2290 | Vestaboard encoding, board capture history |
-| 2287–2400 | TRMNL webhook push, merge variables |
-| 2400–2980 | settings normalization/persistence, Flask routes |
-| 2980–3290 | push scheduler, quiet hours, startup persistence check |
+| 313–525 | `TRMNL_MK_*` Liquid markup constants, one per device layout |
+| 530–1855 | the control-panel HTML/CSS/JS, inline as Python strings |
+| 1860–2070 | WSDOT fetch, route/direction logic, delay parsing |
+| 2075–2210 | Vestaboard encoding, board capture history |
+| 2214–2340 | per-board layout templates (sandboxed Jinja) |
+| 2340–2610 | Vestaboard/TRMNL push, merge variables |
+| 2610–3210 | settings normalization/persistence, Flask routes |
+| 3213–3530 | push scheduler, quiet hours, startup persistence check |
 
 `assets/trmnl-markup.liquid` is a standalone copy of the markup and must be kept in sync
 with the `TRMNL_MK_*` constants when they change.
@@ -89,6 +90,23 @@ Also: **in Liquid an empty string is truthy** (only `nil`/`false` are falsy), so
 Vestaboard: check `vb_dimensions(model)` before assuming grid size — Note is 3 rows × 15 cols,
 Flagship is 6 × 22, and markup that fits one clips on the other.
 
+## Vestaboard quiet hours and board templates
+
+A board's own Quiet Hours (set in the Vestaboard app / web2.vestaboard.com) **drop incoming
+messages**, and the Read/Write API cannot read or set them — it only does read message, send
+message, get/set transition. So the pre-sleep message is pushed `quiet.sleep_lead_min`
+minutes (default 3) *before* our quiet window's start time, and ferry pushes stop at that
+same early moment so nothing overwrites the goodnight. `_in_quiet_hours()` implements the
+shift; the wake time is not shifted.
+
+A board can override the built-in layout with `board['template']` — a sandboxed Jinja
+template, one rendered line per board row (`LEFT | RIGHT` splits a row, anything else
+centers). Two gotchas: the env uses `trim_blocks`/`lstrip_blocks` so an `{% if %}` on its
+own line doesn't emit a blank row, and `BOARD_TEMPLATE_EXAMPLES` is **per model** because a
+6-row flagship example loses its conditional line when truncated to a 3-row Note. Anything
+new added to `board_template_context()` should be top-level and pre-formatted, and any new
+call site of `format_vestaboard_message()` must pass `template=`.
+
 ## Releases
 
 Use `/release`. The short version: tests → commit → push `main` → `gh release create vX.Y.Z`

README.md

@@ -107,6 +107,37 @@ message once — a line of text or a captured layout. Click **Read current board
 grab whatever is on the board and save it to that board's capture history, then pick
 any capture as the sleep message.
 
+The sleep message goes out a few minutes *before* the start time (3 by default,
+adjustable per board). A Vestaboard's own Quiet Hours — set in the Vestaboard app, and
+not reachable from the Read/Write API — drop incoming messages, so a goodnight pushed at
+the exact start time can be swallowed and leave the ferry layout up all night. Ferry
+pushes stop at the same early moment, so nothing overwrites the goodnight. Set the lead
+to 0 to fire exactly at the start time.
+
+**Custom board layouts.** Under **Advanced** in the board editor, a template can replace
+the built-in Vestaboard layout without touching the code. One rendered line per board row;
+a line containing `|` splits into left- and right-aligned halves, everything else is
+centered. `{% if %}` / `{% else %}` / `{% endif %}` on their own lines don't emit blank
+rows, so the bottom row can show the delay when there is one and the next ship's name when
+there isn't:
+
+```
+{{ origin }}-{{ dest }} {{ time_short }}
+SPACES: {{ spaces }}
+{% if delay %}
+DELAYED {{ time_short }}
+{% else %}
+{{ vessel }}
+{% endif %}
+```
+
+Available variables — `route`, `route_name`, `origin`, `dest`, `origin_full`, `dest_full`,
+`time`, `time_short`, `vessel`, `spaces`, `delay`, `alert`, `clock`, `clock12`, `date`,
+`docked`, `error`, `has_status`, `rows`, `cols` — are listed with examples in the UI, and
+the board preview updates as you type. Templates render in a sandbox; one that fails shows
+`TEMPLATE ERROR` on the preview instead of pushing a blank board. Leave the box empty for
+the built-in layout.
+
 **Persistence.** All settings are saved on the server as JSON (default
 `/app/data/settings.json`), so they survive restarts and are shared across browsers.
 Mount a volume at `/app/data` to keep them (the Docker quick-start does this).