fix: prepare server 1.3.1

[Priveetee]

Summary

• recover playback when YouTube rejects the active SABR token context
• release replaced SABR sessions and their extractor resources
• bound SABR metadata and segment caches
• align the Server version with TypeType 1.3.1

Production behavior

• videos and Shorts no longer stop after about one minute when the active YouTube context is rejected
• a rejected protected context is invalidated before the replacement session is created
• replacement sessions receive fresh Token material instead of reusing the rejected context
• retired sessions release their background work and extractor resources
• SABR caches remain bounded during long-running playback

Deployment requirements

No database migration, configuration change or environment update is required.

Runtime verification

• beta served Server revision 0b42a14a24f350170870efb310871ebb1fdf884b
• reproduced the failure from #184 at about 69 seconds before the fix
• confirmed one replacement session recovered playback and continued beyond 168 seconds after the fix
• the browser remained at readyState 4 with media buffered ahead and no HTTP failures

Tests

• ./gradlew test
• ./gradlew check
• ./gradlew shadowJar
• git diff --check
• beta runtime playback for the exact video reported in #184

Rollback

• previous stable Server revision: 22dcd6ddcd6b7babd3ab9f2cb184d6dcb37136d2
• previous stable image: ghcr.io/typetype-video/typetype-server@sha256:7aec72c873daad5ef8d187ba315eae2e7eb21843cabd9dd44d2552516f757a89