binarybeachio: Bucket-4 trusted-JWT auth — replaces in-place github.py patch

Migrates this fork to the binarybeachio platform-architecture pivot:
oauth2-proxy at the edge enforces a Zitadel session, the auth-bridge
mints a short-lived RS256 JWT, and a NEW additive endpoint at
/auth/sign-in-trusted/ verifies the JWT, claims its jti against
shared-redis (single-use replay protection, fail-closed), find-or-creates
the User, and starts a Django session via user_login().

Net surface vs. upstream-clean: 1 new view file + 1 url path + 1
exports __init__ entry + 7 reserved error codes (6000-6099 range).
github.py and the GitHub-button rebrand patch are reverted to upstream
— sign-in entry-point UX is now driven by Traefik redirectregex on
/sign-in* in infrastructure/plane/docker-compose.yml.

Replay protection contract: jti claim minted by bridge, consumed via
Redis SETNX with ttl = exp - now + 30s. Documented at
binarybeachio/docs/architecture/bridge-jwt-replay-protection.md.

Public-key transport: BB_BRIDGE_PUBLIC_KEY_URL env points at the
in-cluster bridge's /.well-known/bb-bridge.pub.pem (avoids the
env-PEM corruption issue Coolify has with backslash-escaped keys).
Endpoint is implicitly disabled (404) when env unset — vanilla
upstream behavior preserved.

Storage patches (Patch 2) unchanged. Brand asset preserved (dormant).
Pre-migration source state preserved on branch pre-migration-2026-05-04.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitignore

@@ -113,3 +113,6 @@ build/
 .react-router/
 temp/
 scripts/
+
+# binarybeachio: Cloudflare Wrangler local dev cache (when used for *.binarybeach.io DNS work)
+.wrangler/