P2: Refactor large handler file (server.go)

[BadgerOps]

Large Handler File Needs Refactoring

Priority: P2 - Medium
Estimate: 4 hours
Review Reference: REVIEW.md (P2-1)

Issue

internal/http/server.go is 1171 lines with mixed concerns:

• Route registration
• Request handling
• Business logic (CIDR computation)
• CSV export
• Error handling

Impact: Low - Maintenance difficulty as codebase grows

Solution

Split into logical files:

internal/http/
├── server.go          (100 lines) - Server struct, RegisterRoutes
├── middleware.go      (50 lines)  - Middleware functions
├── handlers_pools.go  (300 lines) - Pool CRUD handlers
├── handlers_accounts.go (200 lines) - Account CRUD handlers
├── handlers_blocks.go (300 lines) - Block enumeration
├── handlers_export.go (200 lines) - Export functionality
├── handlers_health.go (50 lines)  - Health/ready endpoints
├── cidr.go           (150 lines) - CIDR validation/computation
├── helpers.go        (50 lines)  - writeJSON, writeErr
└── types.go          (50 lines)  - apiError, blockInfo, etc.

Acceptance Criteria

• server.go reduced to ~100 lines (Server struct, RegisterRoutes)
• Handlers grouped by resource in separate files
• CIDR logic extracted to cidr.go
• Export functionality in handlers_export.go
• All tests still pass
• No circular dependencies
• Imports cleaned up

Benefits

• Easier navigation and maintenance
• Clear separation of concerns
• Easier to review diffs
• Better code organization for new contributors

Validation

make lint
make test
# Verify all tests pass after refactoring