Cap request body size (HTTP 413)

LimitRequestBodyMiddleware (pure ASGI, registered outermost) rejects request
bodies larger than PIRATS_MAX_BODY_BYTES (default 1 MiB) before they're buffered
into memory: it checks the declared Content-Length first, then counts the bytes
actually streamed so a chunked/length-omitting client can't bypass the header
check. Exposed as services.pirats.maxBodyBytes and documented in the README.

Tested in isolation (Content-Length fast path + streamed path) and through the
real app.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/lib/changelog.js

@@ -6,7 +6,7 @@
 //   - Add a CHANGELOG entry only when a commit changes something players can
 //     see. Skip refactors, tests, and tooling. Keep wording player-facing.
 
-export const VERSION = 11;
+export const VERSION = 12;
 
 // Newest first. Each entry: { version, date: 'YYYY-MM-DD', changes: [string, ...] }.
 export const CHANGELOG = [