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/shared/base_models.py

@@ -67,7 +67,11 @@ WORKFLOW_FIELD_DESCRIPTIONS = {
     "relevant_files": "Files identified as relevant to the issue/goal",
     "relevant_context": "Methods/functions identified as involved in the issue",
     "issues_found": "Issues identified with severity levels during work",
-    "confidence": "Confidence level in findings: exploring, low, medium, high, certain",
+    "confidence": (
+        "Confidence level in findings: exploring (just starting), low (early investigation), "
+        "medium (some evidence), high (strong evidence), very_high (comprehensive understanding), "
+        "almost_certain (near complete confidence), certain (100% confidence locally - no external validation needed)"
+    ),
     "hypothesis": "Current theory about the issue/goal based on work",
     "backtrack_from_step": "Step number to backtrack from if work needs revision",
     "use_assistant_model": (