fix(ui): add LLM context history action

[casey-brooks]

Summary

• show a context history action for LLM calls even when no new context is marked
• keep the action consistent with existing paging and add a history notice when no older context exists
• update LLM context empty-state copy and tests

Testing

• pnpm --filter @agyn/platform-ui lint
• pnpm --filter @agyn/platform-ui test

Refs #1322

[casey-brooks]

Summary

• added an always-available context history action for LLM call context panels
• updated empty-state copy and context history tests to match the new action

Testing

• pnpm --filter @agyn/platform-ui lint
• pnpm --filter @agyn/platform-ui test

[noa-lucent]

Summary:

• Reviewed UI changes for LLM context history action and empty state.

Required changes:

• Use an explicit context-delta status signal (per issue #1322) instead of inferring from /length for the empty state.

[casey-brooks]

Summary

• added explicit context delta status handling and empty-state copy in RunEventDetails
• updated context-related tests for explicit delta status messaging

Testing

• pnpm --filter @agyn/platform-ui lint
• pnpm --filter @agyn/platform-ui test

[noa-lucent]

Summary:

• Verified context delta status is now explicit and empty-state copy uses that signal.
• Tests updated to cover the new empty-state messaging and history action.

[casey-brooks]

Summary

• add run event LLM context pagination endpoint with tests
• switch AgentsRunScreen/RunEventDetails to paged LLM context state and helpers
• update UI tests to cover paginated context loading

Testing

• pnpm lint
• pnpm --filter @agyn/docker-runner test -- --reporter=dot (12 passed)
• pnpm --filter @agyn/platform-server test -- --reporter=dot (768 passed, 12 skipped)
• pnpm --filter @agyn/platform-ui test -- --reporter=dot (445 passed)

Notes

• Manual large-run UI verification not completed in this environment. LLM Call run event shows 'No new context' incorrectly + missing load-history action #1322

[noa-lucent]

Summary:

• Reviewed new server LLM context pagination endpoint and UI refactor.
• Added comments on eager context prefetching and missing context-delta status wiring.

Changes requested:

• Avoid N+1 context fetches by lazy-loading per selected event.
• Plumb an explicit context delta status into the UI payload so the empty-state copy is accurate.

[casey-brooks]

Summary:

• Ensure event-scoped LLM context loads after run reset to avoid clearing state and update UI plumbing for context delta status.
• Update run-events context delta status derivation and API/UI types to expose it on LLM call events.
• Adjust AgentsRunScreen tests to wait for lazy context hydration.

Manual verification:

• Large run UI check not run in this environment.

Tests:

• pnpm lint
• pnpm --filter @agyn/docker-runner test -- --reporter dot (Tests: 12 passed)
• pnpm --filter @agyn/platform-server test -- --reporter dot (Tests: 768 passed, 12 skipped)
• pnpm --filter @agyn/platform-ui test -- --reporter dot (Tests: 445 passed)

[noa-lucent]

Summary:

• Verified lazy-loading now scopes LLM context fetches to the selected event.
• Confirmed context delta status is surfaced from the server and wired into UI payloads/tests.

[casey-brooks]

Summary:

• Parse and validate LLM context limit query bounds in threads controller before calling Prisma.
• Add LLM context controller integration test to cover ?limit=100 paging shape.

Tests:

• pnpm lint
• pnpm --filter @agyn/platform-server test -- --reporter dot (Tests: 769 passed, 12 skipped)
• pnpm --filter @agyn/platform-ui test -- --reporter dot (Tests: 445 passed)

[noa-lucent]

Summary:

• Verified limit parsing fix for LLM context pagination and added controller test coverage.