fix: code audit — security, correctness, and robustness fixes

Security:
- Path traversal: validate user_id, case_id, skill_name against safe regex
- Input sanitization in memory.py and skills.py file path construction

Correctness:
- ISR timezone: replace hardcoded UTC+3 with ZoneInfo("Asia/Jerusalem") for DST
- save_rule: use EspoCrmApiError.status_code instead of fragile string matching
- Background tasks: store references to prevent GC before completion
- Lock race: use dict.setdefault() for atomic lock creation
- Version: health.py now matches main.py (0.2.0)
- Skill names: normalized to lowercase for dedup consistency

Build:
- Dockerfile: install from pyproject.toml instead of hardcoded pip list
- Remove unused mcp>=1.0.0 dependency from pyproject.toml

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Dockerfile

@@ -4,14 +4,14 @@ RUN apt-get update && apt-get install -y --no-install-recommends curl && rm -rf
 
 WORKDIR /app
 
-# Copy application
+# Copy project files
 COPY pyproject.toml .
 COPY api/ api/
 COPY mcp_server/ mcp_server/
 COPY config/ config/
 
-# Install dependencies
-RUN pip install --no-cache-dir fastapi "uvicorn[standard]" httpx pydantic openai pyyaml
+# Install dependencies from pyproject.toml
+RUN pip install --no-cache-dir .
 
 # Create persistent data directories
 RUN mkdir -p /opt/data/skills /opt/data/profiles /opt/data/cases