Web client (warp-web) with E2EE, and two sync fixes

apps/web: a Matrix client for the browser on Vue 3, Tailwind and
matrix-js-sdk, built on @warp/ui. Like the admin panel it is an optional,
separate service: warp-web embeds the built app, serves /config.json and
proxies only /_matrix/client and /_matrix/media to the homeserver (or,
with -public-homeserver, lets the browser call it directly).
Sign-in and sign-up with registration tokens, room list, timeline with
back-pagination, text, images, video and files over authenticated media,
local echo with sent/read/failed states, receipts, typing, invites,
creating, joining and leaving rooms, room info, settings, phone layout.
End-to-end encryption through the Rust crypto: encrypted messages and
files, emoji verification, key backup setup and restore.

apps/ui: WRoomItem, WMessageBubble and WComposer from the brand package,
and the icons the client needs.

syncapi fixes found with the client:
- A room joined inside the sync window was sent as the join alone with
  limited: false, so clients thought they had the whole room. It is now
  read like an initial sync; a profile change is not mistaken for a join.
- A live typing notification was reported on every sync, so every long
  poll returned at once while anybody typed. Typing now has a position
  in the sync token and is reported when it changes, including the empty
  list when the last person stops.

Also: Dockerfile, a `web` compose profile, Makefile targets, a CI job
with a proxy smoke test, docs. PLAN.md moves out of the repository.

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

apps/ui/README.md

@@ -46,6 +46,9 @@ The stylesheet brings in:
 | `WBanner` | feedback; always icon and words, never colour alone |
 | `WDialog` | modal on the native `<dialog>` |
 | `WSpinner` | progress |
+| `WRoomItem` | a row of the room list: avatar, name, preview, time, unread counter |
+| `WMessageBubble` | a message with sender, time and delivery status (`sending`, `sent`, `read`, `failed`) |
+| `WComposer` | the message field: attach, Enter sends, Shift+Enter adds a line |
 
 ## Where things come from
 
@@ -58,5 +61,7 @@ apps on the same grid: 24px, 1.75 stroke, round caps and joins.
 The fonts are Outfit, Figtree and JetBrains Mono under the SIL Open Font
 License.
 
-The Matrix store (Pinia over matrix-js-sdk) joins this package with the web
-client.
+The three chat components are the brand package's `RoomItem`,
+`MessageBubble` and `Composer`. The Matrix state itself is not here: it
+lives with the web client (`apps/web/src/stores`, `apps/web/src/matrix`),
+which the desktop app will reuse as a whole.