chore: Bump version to 0.7.0

Version updates:
- README.md badge: 0.6.0 → 0.7.0
- cli/pyproject.toml: 0.6.0 → 0.7.0
- backend/pyproject.toml: 0.6.0 → 0.7.0
- sdk/pyproject.toml: 0.6.0 → 0.7.0
- ai/pyproject.toml: 0.6.0 → 0.7.0

Add CHANGELOG.md with comprehensive release notes for 0.7.0:
- Secret detection workflows (gitleaks, trufflehog, llm_secret_detection)
- AI module and agent integration
- Temporal migration completion
- CI/CD integration
- Documentation updates
- Bug fixes and improvements

Update llm_analysis default model to gpt-5-mini

backend/pyproject.toml

@@ -1,6 +1,6 @@
 [project]
 name = "backend"
-version = "0.6.0"
+version = "0.7.0"
 description = "FuzzForge OSS backend"
 authors = []
 readme = "README.md"

backend/toolbox/workflows/llm_analysis/metadata.yaml

@@ -15,7 +15,7 @@ workspace_isolation: "shared"
 
 default_parameters:
   agent_url: "http://fuzzforge-task-agent:8000/a2a/litellm_agent"
-  llm_model: "gpt-4o-mini"
+  llm_model: "gpt-5-mini"
   llm_provider: "openai"
   max_files: 5