feat(client): fetch the media apps, the player, settings and search on first use

apps.js registers Videos, Music, Photos and every settings pane through
lazy.js; the group page does the same for the video player and the
settings panel, and the shell for the search page. The first download
goes from 49 modules / 386 KB gzip to 37 / 289 KB; opening Music now
fetches music-app.js and media-tiles.js and nothing of Videos.
test_first_load_is_lean holds the eager graph; test_spa_imports checks
that every on-demand load names an export that exists.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/docs/MESHBAY_DESIGN.md b/docs/MESHBAY_DESIGN.md
index f260d6e..13e0cab 100644
--- a/docs/MESHBAY_DESIGN.md
+++ b/docs/MESHBAY_DESIGN.md
@@ -2449,7 +2449,12 @@ There is no folder-browsing protocol and this does not add one.
 1. **`<name>-app.js`** exporting a component with the standard props shape.
 2. **Register it** in the registry. `key` is the wire identifier: it must match the
    node's allow-list and it is the row the application's directories are stored
-   under. **One identifier per application, everywhere.**
+   under. **One identifier per application, everywhere.** Register the
+   component — and its settings pane — through `lazy(() => import('./<name>-app.js'),
+   'Name')` (`lazy.js`), not a static import: the module is then fetched the first
+   time the tab is opened instead of with the first page, and
+   `test_first_load_is_lean.py` (add the file to its `ON_DEMAND` set) refuses a
+   static import that would bring it back.
 3. **`<name>-app-settings.js`** if it has anything to configure. Do not import the
    settings page — that is the cycle in §9.1.
 4. **Add the key to the node's allow-list**, and — if the application keeps