Fix get ans tool

[swati510]

Upgrade get_answer tool with question-aware symbol promotion: extracts identifiers
from the question, promotes matching symbols to the top of retrieval results, and
attaches source-body excerpts so the LLM can answer specific-method questions without
hedging

• Add hedge detection to downgrade confidence when the LLM admits it can't answer,
  and bypass stale hedged cache entries for re-synthesis
• Add identifier-citation gate to downgrade confidence when named symbols aren't
  found in top retrieval hits

Related Issues

Fixes #84

Test Plan

• Tests pass (pytest)
• Lint passes (ruff check .)
• Web build passes (npm run build) (if frontend changes)

Checklist

• My code follows the project's code style
• I have added tests for new functionality
• All existing tests still pass
• I have updated documentation if needed

[RaghavChamadiya]

LGTM