Update confidence enum values across workflow tools

Added new confidence values (very_high, almost_certain) to all workflow tools
to provide more granular confidence tracking. Updated enum declarations in:
- analyze.py, codereview.py, debug.py, precommit.py, secaudit.py, testgen.py
- Updated debug.py's get_required_actions to handle new confidence values
- All tools now use consistent 7-value confidence scale
- refactor.py kept its unique scale (exploring/incomplete/partial/complete)

Also fixed model thinking configuration:
- Added very_high and almost_certain to MODEL_THINKING_PREFERENCES
- Set medium thinking for very_high, high thinking for almost_certain
- Updated prompts to clarify certain means 100% local confidence

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

tools/tracer.py

@@ -86,8 +86,10 @@ TRACER_WORKFLOW_FIELD_DESCRIPTIONS = {
     "confidence": (
         "Indicate your current confidence in the tracing analysis completeness. Use: 'exploring' (starting analysis), "
         "'low' (early investigation), 'medium' (some patterns identified), 'high' (comprehensive understanding), "
-        "'complete' (tracing analysis finished and ready for output). Do NOT use 'complete' unless the tracing "
-        "analysis is thoroughly finished and you have a comprehensive understanding of the code relationships."
+        "'very_high' (very comprehensive understanding), 'almost_certain' (nearly complete tracing), "
+        "'certain' (100% confidence - tracing analysis is finished and ready for output with no need for external model validation). "
+        "Do NOT use 'certain' unless the tracing analysis is thoroughly finished and you have a comprehensive understanding "
+        "of the code relationships. Using 'certain' means you have complete confidence locally and prevents external model validation."
     ),
     "trace_mode": "Type of tracing: 'ask' (default - prompts user to choose mode), 'precision' (execution flow) or 'dependencies' (structural relationships)",
     "target_description": (