release: kode-bridge 0.5.1

[Tunglies]

Release 0.5.1

Promotes the validated dev head to main for the 0.5.1 release.

Includes:

• restored Unix peer UID/GID in RequestContext::client_info
• restored Windows server PID verification and optional LocalSystem enforcement
• verification on every new physical Windows named-pipe connection, including reconnects, pooled replacements, and large-PUT fallback connections
• configured Unix listener modes on macOS with socket identity revalidation
• restored 0.4.2 identity-facing public API and 0.5.1 migration documentation

Validation:

• source PR fix: restore IPC identity verification for 0.5.1 #24 completed all candidate checks
• post-merge dev CI run 32374650940 passed all 7 jobs on Ubuntu, macOS, and Windows
• native Windows identity and transport coverage passed

Post-merge main CI must pass before the annotated v0.5.1 tag is pushed. That tag triggers the repository Release workflow, which publishes the crate and creates the GitHub Release.

Source PR: #24