chore: enhance project metadata, tooling, and documentation

**Project Configuration:**
- Enhance pyproject.toml with comprehensive metadata, keywords, and classifiers
- Add LICENSE file (MIT) for proper open-source distribution
- Add PUBLISHING.md with comprehensive publishing guidelines
- Update .gitignore to exclude tool artifacts (.cache, .pytest_cache, .ruff_cache, .ty_cache)
- Ignore documentation working directories (.docs, .full-review, docs/plans, docs/sessions)

**Documentation:**
- Add extensive Unraid API research documentation
  - API source code analysis and resolver mapping
  - Competitive analysis and feature gap assessment
  - Release notes analysis (7.0.0, 7.1.0, 7.2.0)
  - Connect platform overview and remote access documentation
- Document known API patterns, limitations, and edge cases

**Testing & Code Quality:**
- Expand test coverage across all tool modules
- Add destructive action confirmation tests
- Improve test assertions and error case validation
- Refine type annotations for better static analysis

**Tool Improvements:**
- Enhance error handling consistency across all tools
- Improve type safety with explicit type annotations
- Refine GraphQL query construction patterns
- Better handling of optional parameters and edge cases

This commit prepares the project for v0.2.0 release with improved
metadata, comprehensive documentation, and enhanced code quality.

Co-authored-by: Claude <noreply@anthropic.com>

unraid_mcp/tools/notifications.py

@@ -157,7 +157,7 @@ def register_notifications_tool(mcp: FastMCP) -> None:
                     "title": title,
                     "subject": subject,
                     "description": description,
-                    "importance": importance.upper() if importance else "INFO",
+                    "importance": importance.upper(),
                 }
                 data = await make_graphql_request(
                     MUTATIONS["create"], {"input": input_data}
@@ -194,7 +194,7 @@ def register_notifications_tool(mcp: FastMCP) -> None:
                 data = await make_graphql_request(MUTATIONS["archive_all"], variables)
                 return {"success": True, "action": "archive_all", "data": data}
 
-            return {}
+            raise ToolError(f"Unhandled action '{action}' — this is a bug")
 
         except ToolError:
             raise