#8888: fix: increase tool result/error context limits

## Problem Tool outputs are truncated before being passed back to the model: - **Tool results:** 8000 chars (loses large diffs, test output) - **Tool errors:** 400 chars (loses stack traces) This causes batch processing failures where the model can't understand what went wrong or what the full output was. ## Solution Increase limits to preserve more context: - `TOOL_RESULT_MAX_CHARS`: 8000 → 16000 - `TOOL_ERROR_MAX_CHARS`: 400 → 2000 ## Impact - Better batch processing reliability - Model can see full stack traces for debugging - Large outputs (git diff, test results) are less likely to be truncated ## Testing Manual testing with batch operations showed improved error recovery and context preservation. <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This PR increases the maximum size of tool outputs passed back to the model in `src/agents/pi-embedded-subscribe.tools.ts`, raising tool result truncation from 8k→16k characters and tool error message truncation from 400→2000 characters. The change is implemented by updating the constants used by `truncateToolText` (for `content[].text`) and `normalizeToolErrorText`/`extractToolErrorMessage` (for error summaries), with added inline documentation explaining the intent (preserve more diff/test output and stack trace context). <h3>Confidence Score: 5/5</h3> - This PR is safe to merge with minimal risk. - Change is confined to two constants that control truncation length for tool result text and single-line error summaries; the logic paths and function behavior remain unchanged aside from allowing more context through. - No files require special attention <!-- greptile_other_comments_section --> _{(4/5) You can add custom instructions or style guidelines for the agent [here](https://app.greptile.com/review/github)!} **Context used:** - Context from `dashboard` - CLAUDE.md ([source](https://app.greptile.com/review/custom-context?memory=fd949e91-5c3a-4ab5-90a1-cbe184fd6ce8)) - Context from `dashboard` - AGENTS.md ([source](https://app.greptile.com/review/custom-context?memory=0d0c8278-ef8e-4d6c-ab21-f5527e322f13)) <!-- /greptile_comment -->