v5.0.0: protocol v5 and the browser frontend

Protocol v5 replaces newline lines with bounded [u32 len][text] frames and REQ/RES/EVT envelopes. Requests carry correlation ids and the server replays the last 256 replies per connection, so a gateway retry cannot double-debit and a late reply cannot clobber a newer request. HELLO/PONG carry server time; crash rounds announce started_at and push coalesced 10 Hz ticks. Crash now commits sha256(seed) before a round and reveals the seed when it ends, so clients recompute the crash point.

Adds the webd/ gateway: one blocking thread, one ClientCore and one pinned upstream TLS connection per session, an HttpOnly session cookie, takeover, and a 60-second grace window. The browser sends Command JSON and renders View JSON; it never speaks the game protocol or stores credentials.

Adds the vanilla TypeScript browser app at /play/ (login, lobby, all four games, history, notices, crash verification), the nginx /play and /ws routes, and the headless DOM smoke test. webd and the app stay out of the TUI/GUI/server build graph.

The client/server version moves to 5.0.0 in lockstep; v4 peers are refused at HELLO.

1 files changed, 2 insertions, 1 deletions

diff --git a/docs/adr/0001-gui-frontend-architecture.md b/docs/adr/0001-gui-frontend-architecture.md
index 44dca32..e4dd5ac 100644
--- a/docs/adr/0001-gui-frontend-architecture.md
+++ b/docs/adr/0001-gui-frontend-architecture.md
@@ -1,6 +1,7 @@
 # 0001 — GUI is a second frontend over a shared core
 
-Status: accepted, 2026-11-01
+Status: accepted, 2026-11-01; the "no browser" constraint is superseded by
+[0003](0003-web-gateway.md), which adds a browser frontend through a gateway.
 
 ## Context