Reduce memory pressure in heavy threads

[jacobjmc]

Summary

• evict inactive thread item caches so loaded thread state does not grow without bound
• materialize inline data URL images to temp files before sending them to the frontend
• virtualize large message lists and add regression coverage for eviction, virtualization, and image conversion

Testing

• npm run typecheck
• npm run test -- src/features/messages/components/Messages.test.tsx
• npm run test -- src/features/threads/hooks/useThreads.integration.test.tsx
• cargo test frontend_image_value_materializes_data_urls_to_temp_files --lib
• npm run test -- src/features/threads/hooks/useThreadsReducer.test.ts src/utils/threadItems.test.ts src/features/composer/components/ComposerInput.attachments.test.tsx
• cd src-tauri && cargo check

---

Summary by cubic

Reduces memory use in thread-heavy sessions by evicting inactive thread caches, virtualizing long message lists, and materializing inline image data URLs to temp files. Keeps the UI responsive and prevents unbounded growth.

• New Features
  • Evict cached items for inactive threads beyond 5; active/processing/reviewing/pinned threads are protected. Threads auto-resume when reopened.
  • Virtualize the messages list when it exceeds 30 rows using @tanstack/react-virtual to cut DOM nodes and improve scroll performance.
  • Convert inline data:image/* URLs to temp files in the Rust core, deduplicate by hash, and reuse the path to reduce memory and payload size, with 8 MB pre/post-decode guards for base64 images.
  • Added focused tests for eviction, virtualization, and image materialization.

^{Written for commit efbbf16. Summary will update on new commits.}

[cubic-dev-ai]

1 issue found across 7 files

Prompt for AI agents (unresolved issues)

Check if these issues are valid — if so, understand the root cause of each and fix them. If appropriate, use sub-agents to investigate and fix each issue separately.


<file name="src-tauri/src/shared/codex_core.rs">

<violation number="1" location="src-tauri/src/shared/codex_core.rs:1132">
P2: Add a byte-size limit before/after base64 decode for data URL images. Decoding unbounded payloads can cause high memory usage or OOM under large inline images.</violation>
</file>

_{Reply with feedback, questions, or to request a fix. Tag @cubic-dev-ai to re-run a review.}

[Copilot]

@jacobjmc I've opened a new pull request, #10, to work on those changes. Once the pull request is ready, I'll request review from you.