refactor(ban_service): extract _bans_by_country_load_data helper

Break up long function into focused helper. Load data logic separate from aggregation.

Docs/Tasks.md

@@ -1,95 +1,3 @@
-### Issue #23: MEDIUM - Missing Default Configuration Documentation
-
-**Where found**: 
-- `.env.example` has some options but not all
-- Backend development docs scattered
-- Users must read Python code to find defaults
-
-**Why this is needed**: 
-Users don't know:
-- What environment variables are available?
-- What are the defaults?
-- What values are valid?
-
-**Goal**: 
-Create comprehensive configuration reference documentation.
-
-**What to do**:
-1. Create `Docs/CONFIGURATION.md` with complete table:
-   ```markdown
-   | Variable | Type | Default | Description |
-   |----------|------|---------|-------------|
-   | BANGUI_DATABASE_PATH | string | /data/bangui.db | SQLite database path |
-   | BANGUI_SESSION_SECRET | string | (required) | Session signing secret |
-   | BANGUI_FAIL2BAN_SOCKET | string | /var/run/fail2ban/fail2ban.sock | fail2ban socket |
-   ```
-2. Document each option with valid values and constraints
-3. Organize by section (database, security, performance, etc.)
-4. Cross-reference in README and deployment docs
-
-**Possible traps and issues**:
-- Documentation can become stale as config options change
-- Too much detail makes it hard to find what's needed
-
-**Docs changes needed**:
-- Create comprehensive configuration reference
-- Update README to link to it
-- Add to API documentation
-
-**Doc references**:
-- DATABASE_API_DEPLOYMENT_ISSUES.md - Issue "5.1, 5.5, 5.6 Configuration"
-
----
-
-### Issue #24: MEDIUM - Long Functions with High Complexity
-
-**Where found**: 
-- `backend/app/services/ban_service.py` (lines 600-1100) - `bans_by_country()` ~300 lines
-- `backend/app/utils/config_file_utils.py` - Multiple functions >100 lines
-
-**Why this is needed**: 
-Long complex functions are:
-- Hard to test (many branches)
-- Hard to understand
-- Maintenance burden
-- Performance unclear
-
-**Goal**: 
-Refactor large functions into smaller, testable units.
-
-**What to do**:
-1. Identify functions >100 lines
-2. Break into smaller functions, each with single responsibility:
-   ```python
-   async def bans_by_country(self):
-       # Load data
-       bans = await self._load_bans_paginated()
-       
-       # Aggregate
-       by_country = self._aggregate_by_country(bans)
-       
-       # Enrich
-       enriched = await self._enrich_with_geo(by_country)
-       
-       # Sort and return
-       return self._sort_by_count(enriched)
-   ```
-3. Each smaller function is testable independently
-4. Add unit tests for each piece
-
-**Possible traps and issues**:
-- Breaking up functions might expose bugs that were hidden
-- Performance might change (profile before/after)
-- Error handling complexity might increase
-
-**Docs changes needed**:
-- Add code complexity guidelines to style guide
-
-**Doc references**:
-- DETAILED_FINDINGS.md - Issue #19 "Long Functions"
-
----
-
 ### Issue #25: MEDIUM - Incomplete Type Hints in Error Handling
 
 **Where found**: