[plan] Optimize prompt token usage in workflow runs

[github-actions]

Objective

Reduce token consumption in workflow runs by trimming verbose prompts and enabling summarization where appropriate.

Context

Token usage spiked ~4x to 1.71M tokens across the last 10 runs, suggesting inefficient prompt construction or unnecessarily verbose outputs.

Approach

1. Analyze the last 10 workflow runs to identify top token consumers:
   • Use gh aw logs or audit commands to extract token usage per step
   • Identify prompts/steps with highest token counts
2. Review prompt construction in high-cost steps:
   • Look for redundant context or instructions
   • Check for unnecessary verbosity in system prompts
   • Identify opportunities for summarization
3. Implement optimizations:
   • Trim verbose instructions where possible
   • Enable output summarization for intermediate steps
   • Remove redundant context from prompts
4. Validate changes don't reduce quality

Files to Modify

• .github/workflows/*.md - Workflow source files with prompts
• Any agent configuration files affecting prompt construction

Acceptance Criteria

• Token usage reduced by at least 50% (target: <850k for 10 runs)
• Output quality maintained (no regression in agent effectiveness)
• Top 3 token-consuming steps identified and optimized
• Changes documented with before/after token counts

Estimated Effort

Medium (3-5 hours)
Related to #6857

AI generated by Plan Command for discussion #6855