feat: Add Docker infrastructure with Caddy and startup scripts (#25, #26)

Issue #25 - Docker multi-service infrastructure:
- Create docker/Dockerfile with multi-stage build, git support, port 8080
- Create docker/docker-compose.yml with app + Caddy services
- Create docker/Caddyfile for HTTPS termination and reverse proxy
- Create docker/.env.example with configuration template

Issue #26 - Startup scripts and tests:
- Create scripts/start.sh for production startup with env validation
- Create scripts/healthcheck.sh for Docker health checks
- Add health endpoint tests to test_mcp_endpoints.py
- Fix middleware order (HealthCheckBypass must wrap BearerAuth)
- Fix pyproject.toml testpaths to use 'tests' directory
- Update test_config.py for new defaults (0.0.0.0:8080)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docker/.env.example

@@ -0,0 +1,38 @@
+# Gitea MCP Remote - Docker Environment Configuration
+#
+# Copy this file to .env and fill in your values:
+#   cp .env.example .env
+
+# =============================================================================
+# Required Configuration
+# =============================================================================
+
+# Gitea instance URL (e.g., https://gitea.example.com)
+GITEA_URL=https://gitea.example.com
+
+# Gitea API token for authentication
+# Generate at: Settings -> Applications -> Generate New Token
+GITEA_TOKEN=your_gitea_api_token_here
+
+# Default repository owner/organization
+GITEA_OWNER=your_username_or_org
+
+# =============================================================================
+# Optional Configuration
+# =============================================================================
+
+# Default repository name (optional - can be specified per-request)
+GITEA_REPO=
+
+# Bearer token for MCP endpoint authentication (optional)
+# If set, clients must include "Authorization: Bearer <token>" header
+AUTH_TOKEN=
+
+# MCP authentication mode: 'required', 'optional', or 'none'
+MCP_AUTH_MODE=optional
+
+# Tool filtering (optional, comma-separated)
+# ENABLED_TOOLS=list_issues,create_issue,list_labels
+# DISABLED_TOOLS=delete_issue,delete_label
+ENABLED_TOOLS=
+DISABLED_TOOLS=