Fix cross-tab session ownership race

[chen21019]

Root cause

• Shared cookie and storage state let an older tab route passive failures through the destructive logout path.
• OIDC callbacks did not retain the browser-session generation captured before leaving the origin.

Changes

• Separate passive invalidation from explicit logout.
• Add high-entropy session generation, safe same-origin return targets, Web Locks with a fail-closed IndexedDB lease fallback, guarded cookie commit/readback, and automatic tab adoption.
• Capture generations for requests, timers, WebSockets, routes, and OIDC transactions.
• Keep JWT values out of Web Storage, URLs, and logs.
• Bump Web Console to 1.6.117 and document the compatibility contract.

Verification

• Full browser-unit suite: 467 passed, 0 failed.
• Session-focused suite: 34 passed, including 100 deterministic delayed-response TOTP/Passkey race iterations.
• Production stack.ascdc.tw and HAProxy were not modified.

Requires PastureStack/orchestration-engine 0.183.302 or newer for session-bound server logout protection.