refactor(backend): clean up models setup, improve ip utils, add adr docs

- Extract ADR documents for architectural decisions (SQLite, FastAPI, React, APScheduler, Scheduler)
- Refactor setup.py: improve code structure and readability
- Add IP validation utilities with test coverage
- Update frontend components (BanTable, HistoryPage)
- Add pre-commit hooks and CONTRIBUTING.md
- Add .editorconfig for consistent coding standards

Docs/Tasks.md

@@ -1,46 +1,3 @@
-### Issue #27: MEDIUM - Inconsistent Error Handling Patterns
-
-**Where found**: 
-- `ban_service.py` - Raises exceptions
-- `server_service.py` - Returns defaults silently
-- `jail_service.py` - Mixed approach
-
-**Why this is needed**: 
-Different services have different error handling contracts. Callers don't know what to expect.
-
-**Goal**: 
-Establish clear error handling contract for all services.
-
-**What to do**:
-1. Document error handling patterns:
-   ```python
-   class ServiceErrorContract:
-       """
-       ABORT_ON_ERROR: Raise exception, let router handle
-       RETURN_DEFAULT: Return empty result, log warning
-       PARTIAL_RESULT: Return partial success with error list
-       """
-   ```
-2. Each service method documents which pattern it follows
-3. Routers handle errors consistently
-4. Update service protocols
-
-**Possible traps and issues**:
-- Users of service must know pattern
-- Switching patterns is breaking change
-
-**Docs changes needed**:
-- Create service development guide with error patterns
-
-**Doc references**:
-- DETAILED_FINDINGS.md - Issue "Inconsistent Error Handling"
-
----
-
-## LOWER PRIORITY ISSUES (LOW-MEDIUM)
-
----
-
 ### Issue #28: LOW-MEDIUM - Missing Pre-Commit Hooks
 
 **Where found**: