Implement TracePath tool for static call path analysis

Add comprehensive TracePath tool that predicts and explains full call paths
and control flow without executing code. Features include:

**Core Functionality:**
- Static call path prediction with confidence levels (🟢🟡🔴)
- Multi-language support (Python, JavaScript, TypeScript, C#, Java)
- Value-driven flow analysis based on parameter combinations
- Side effects identification (database, network, filesystem)
- Polymorphism and dynamic dispatch analysis
- Entry point parsing for multiple syntax patterns

**Technical Implementation:**
- Hybrid AI-first architecture (Phase 1: pure AI, Phase 2: AST enhancement)
- Export formats: Markdown, JSON, PlantUML
- Confidence threshold filtering for speculative branches
- Integration with existing tool ecosystem and conversation threading
- Comprehensive error handling and token management

**Files Added:**
- tools/tracepath.py - Main tool implementation
- systemprompts/tracepath_prompt.py - System prompt for analysis
- tests/test_tracepath.py - Comprehensive unit tests (32 tests)

**Files Modified:**
- server.py - Tool registration
- tools/__init__.py - Tool exports
- systemprompts/__init__.py - Prompt exports

**Quality Assurance:**
- All 449 unit tests pass including 32 new TracePath tests
- Full linting and formatting compliance
- Follows established project patterns and conventions
- Multi-model validation with O3 and Gemini Pro insights

**Usage Examples:**
- "Use zen tracepath to analyze BookingManager::finalizeInvoice(invoiceId: 123)"
- "Trace payment.process_payment() with confidence levels and side effects"

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

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

systemprompts/__init__.py

@@ -10,6 +10,7 @@ from .precommit_prompt import PRECOMMIT_PROMPT
 from .refactor_prompt import REFACTOR_PROMPT
 from .testgen_prompt import TESTGEN_PROMPT
 from .thinkdeep_prompt import THINKDEEP_PROMPT
+from .tracepath_prompt import TRACEPATH_PROMPT
 
 __all__ = [
     "THINKDEEP_PROMPT",
@@ -20,4 +21,5 @@ __all__ = [
     "PRECOMMIT_PROMPT",
     "REFACTOR_PROMPT",
     "TESTGEN_PROMPT",
+    "TRACEPATH_PROMPT",
 ]