API key scope resolution fixed; media retention leases renewed

What's Changed

Features

• feat(trace): perf telemetry for the lazy JSON viewer (LFE-14419) by @nkabardin in https://github.com/langfuse/langfuse/pull/15422
• feat: refine event filter options using active filters by @sumerman in https://github.com/langfuse/langfuse/pull/15424
• feat(v4): improve SDK migration detection by @maxdeichmann in https://github.com/langfuse/langfuse/pull/15385

Fixes

• fix: renew media retention leases during blob cleanup by @sumerman in https://github.com/langfuse/langfuse/pull/15416
• fix(mobile): header title crush on long labels + tighten spacing (LFE-11067) by @nkabardin in https://github.com/langfuse/langfuse/pull/15420
• fix: Preserve accurate retention backlog gauges after cleanup by @sumerman in https://github.com/langfuse/langfuse/pull/15425
• fix(v4): show minimum SDK upgrade version by @maxdeichmann in https://github.com/langfuse/langfuse/pull/15449
• fix(v4): update deprecated migration labels and links by @maxdeichmann in https://github.com/langfuse/langfuse/pull/15452
• fix(dashboards): return 404 instead of 500 when updating a missing dashboard by @LysanderKie in https://github.com/langfuse/langfuse/pull/15454
• fix(auth): resolve API key scope publicKey from the verified key, not submitted pk by @Steffen911 in https://github.com/langfuse/langfuse/pull/15456

Chores

• ci(notifications): surface failure reason in Slack, retry Docker manifest publish by @wochinge in https://github.com/langfuse/langfuse/pull/15423
• chore(pricing): add claude-opus-5 default pricing and selectable model entry by @langfuse-bot in https://github.com/langfuse/langfuse/pull/15437
• chore(web): remove legacy v4 migration pages by @maxdeichmann in https://github.com/langfuse/langfuse/pull/15447
• chore(agent): Add skills for React components by @bezbac in https://github.com/langfuse/langfuse/pull/15431

Full Changelog: https://github.com/langfuse/langfuse/compare/v4.0.0-rc.2...v4.0.0-rc.3