[Condense] Skip condense and show error if the context grows

[canrobins13]

Related GitHub Issue

Closes: #3911

Description

Sometimes the context grows rather than shrinking during a context condense. This is an expected edge case under the current implementation: the condense operation preserves the last 3 messages as-is, and tries to summarize the conversation before that point using an LLM call. If the last 3 messages are quite large, and the previous messages are small (or maybe you summarized recently), then you may have reached the threshold, but there's not much that can be done to reduce the context size through summarization while preserving the last 3 messages.
In these cases it's probably best to skip the summary and show the user an error rather than "condensing" the context to a larger size.

Test Procedure

Tried manual and automatic context condenses and observed the error

Type of Change

• 🐛 Bug Fix: Non-breaking change that fixes an issue.
• ✨ New Feature: Non-breaking change that adds functionality.
• 💥 Breaking Change: Fix or feature that would cause existing functionality to not work as expected.
• ♻️ Refactor: Code change that neither fixes a bug nor adds a feature.
• 💅 Style: Changes that do not affect the meaning of the code (white-space, formatting, etc.).
• 📚 Documentation: Updates to documentation files.
• ⚙️ Build/CI: Changes to the build process or CI configuration.
• 🧹 Chore: Other changes that don't modify src or test files.

Pre-Submission Checklist

• Issue Linked: This PR is linked to an approved GitHub Issue (see "Related GitHub Issue" above).
• Scope: My changes are focused on the linked issue (one major feature/fix per PR).
• Self-Review: I have performed a thorough self-review of my code.
• Code Quality:
  • My code adheres to the project's style guidelines.
  • There are no new linting errors or warnings (npm run lint).
  • All debug code (e.g., console.log) has been removed.
• Testing:
  • New and/or updated tests have been added to cover my changes.
  • All tests pass locally (npm test).
  • The application builds successfully with my changes.
• Branch Hygiene: My branch is up-to-date (rebased) with the main branch.
• Documentation Impact: I have considered if my changes require documentation updates (see "Documentation Updates" section below).
• Changeset: A changeset has been created using npm run changeset if this PR includes user-facing changes or dependency updates.
• Contribution Guidelines: I have read and agree to the Contributor Guidelines.

Screenshots / Videos

[samhvw8]

look good, but can we make it grey or yellow text instead of red one ?

[daniel-lxs]

LGTM

[mrubens]

look good, but can we make it grey or yellow text instead of red one ?

I agree! Can you model it after how we show diff errors? Excited for this change in general.