Shell: a quieter menu handle, a calmer fullscreen, live tile settings

Three things the dashboard was making people work for.

**The menu handle.** It was the ProdDash wordmark on a pill hanging past the
bar's bottom edge, which read as a step cut out of the bar. The wordmark goes
back in the bar where it belongs, and the handle becomes a small accent lip on
the bar's bottom edge — the same idea as a tile's notch — that grows under the
pointer so it stays easy to hit without being loud at rest.

That also fixes the animation Safari made a meal of: the old handle
transitioned font-size and line-height, animating text metrics frame by frame
on the way out. Nothing here animates text. The lip rides `--topbar-h`, the
bar's live height, so it tracks the bar's own collapse instead of running a
second animation against it, and its hover growth is width, height and
opacity only.

**Fullscreen.** Fullscreen is for watching, not arranging, so every tile's
title bar now folds away on the way in. A notch still peeks one open, and it
folds back ten seconds after the pointer leaves that tile — coming back to the
tile cancels the countdown. Peeking is a transient class, so a tile's own
hidden/shown preference is untouched and comes back with the screen.

**Tile settings.** Gear settings are display choices — a text size, a filter,
a colour — so they apply as they are changed and save with the layout. Apply
and Cancel are gone; close by clicking away, pressing Escape, or the gear
again. Typing is debounced so a remount doesn't land on every keystroke, and
an unchanged value remounts nothing (a text field fires input and then change
for one edit). The module guide says so now too.

Verified in the browser: settings apply live and persist, no-op changes cost
nothing, all three close paths work, and in fullscreen both heads fold, one
peeks, it folds back at ten seconds, returning the pointer cancels it, and
leaving fullscreen restores everything with no peeks left behind.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

docs/MODULE-GUIDE.md

@@ -97,7 +97,7 @@ the app); its settings are kept for a later reinstall.
 | `style` | no | A stylesheet the shell injects once per module. |
 | `minSize`, `defaultSize` | no | Tile size in grid cells (12 columns wide; rows are ~72 px). Defaults: min 1×1, default 4×3. |
 | `configSchema` | no | **Admin config** — server-wide settings (URLs, ports, keys) edited once at `/admin` for everyone. |
-| `instanceSchema` | no | **Per-tile settings** — chosen in each tile's gear menu and stored with that browser's layout (filters, text sizes, display options). |
+| `instanceSchema` | no | **Per-tile settings** — chosen in each tile's gear menu and stored with that browser's layout (filters, text sizes, display options). They apply as they are changed, so keep them to display choices. |
 | `tiles` | no | Fixed multi-tile list for client-only modules; server modules export a dynamic `tiles()` instead. See **Presenting multiple tiles**. |
 
 Both schemas map field names to specs:
@@ -341,10 +341,13 @@ own in `stop()` anyway.
 - **Any number of instances.** Two transcript tiles with different filters
   is a feature. Keep all state inside `create()`'s closure — no module-level
   mutable state in `client.js`.
-- **Remounts are routine.** When the user edits the tile's gear settings the
-  shell calls `stop()` and starts a fresh instance. When admin config
-  changes, the shell calls your `onConfigChange(cfg)` if you export one,
-  otherwise it remounts you. Either way you must come back cleanly.
+- **Remounts are routine.** Gear settings apply as the user changes them —
+  there is no Apply button — so each change calls `stop()` and starts a fresh
+  instance (typing is debounced, and an unchanged value remounts nothing).
+  Starting cheaply matters: hold connections and timers in the closure and
+  tear them down in `stop()`. When admin config changes, the shell calls your
+  `onConfigChange(cfg)` if you export one, otherwise it remounts you. Either
+  way you must come back cleanly.
 - **The tile can be removed at any moment.** `stop()` is your only notice.
 
 ### Rules for the client