fix(core): cap session shell output

[Oxygen56]

Issue for this PR

Closes #45099

Type of change

• Bug fix
• New feature
• Refactor / code improvement
• Documentation

What does this PR do?

Session shell commands now use the same 50 KiB preview limit as regular shell output. Large command output remains file-backed for paging, while the model-facing session history receives only the bounded preview.

How did you verify your code works?

• A focused before/after check reproduces the old oversized capture and confirms the new model-facing shell output stays within 50 KiB.
• TypeScript syntax and diff checks pass.
• The package test and typecheck commands could not run locally because Bun is unavailable; pull-request CI should run them.

Screenshots / recordings

Not applicable.

Checklist

• I have tested my changes locally
• I have not included unrelated changes in this PR

[github-actions]

Thanks for your contribution!

This PR doesn't have a linked issue. All PRs must reference an existing issue.

Please:

1. Open an issue describing the bug/feature (if one doesn't exist)
2. Add Fixes #<number> or Closes #<number> to this PR description

See CONTRIBUTING.md for details.

[github-actions]

The following comment was made by an LLM, it may be inaccurate:

Potential duplicate found:

• PR fix(core): unify model-visible shell output previews #45109: fix(core): unify model-visible shell output previews
  • This PR appears to address the same concern about standardizing shell output previews for the model. It likely overlaps with PR fix(core): cap session shell output #45136's goal of capping session shell output to 50 KiB to match the regular shell output behavior.

Recommendation: Check if PR #45109 already implements the 50 KiB capping logic or if these PRs address complementary aspects of the same issue (#45099).