feat(modernization): Adopt Go 1.24+ language features and typed JSON responses

[CybotTM]

Summary

This PR comprehensively modernizes the Raybeam codebase to leverage ALL Go improvements from Go 1.19 → 1.25.1 (not just 1.24/1.25 as initially scoped) and enforces complete type safety throughout the API layer. It also analyzes all updated module features for applicable improvements.

Comprehensive Analysis Scope

Go Version Evolution Checked

• ✅ Go 1.20: errors.Join, context.WithCancelCause
• ✅ Go 1.21: slices package, min/max/clear built-ins, maps package, cmp package
• ✅ Go 1.22: Range over integers, enhanced routing
• ✅ Go 1.23: Iterators, unique package
• ✅ Go 1.24: Generic type aliases, Swiss Tables, range-over-func
• ✅ Go 1.25: FlightRecorder API, testing/synctest

Module Updates Analyzed

• ✅ Fiber v2.52.9: Changelog reviewed - bug fixes/performance (no new APIs needed)
• ✅ bbolt v1.4.3: Performance improvements (automatic, no code changes)
• ✅ golang.org/x/crypto v0.42.0: ssh package stable (no relevant changes)
• ✅ cobra v1.10.1: No new features applicable to simple CLI usage
• ✅ simple-ldap-go v1.2.0: API breaking change already handled

Changes Implemented

1. Use slices.DeleteFunc for Efficient Filtering (Go 1.21)

• File: internal/models/ssh_key.go:102
• Change: Replaced manual slice filtering loop with stdlib function
• Before:

  newKeys := make([]SSHKey, 0)
  for _, k := range keys {
      if k.Fingerprint == fingerprint {
          continue
      }
      newKeys = append(newKeys, k)
  }

• After:

  newKeys := slices.DeleteFunc(keys, func(k SSHKey) bool {
      return k.Fingerprint == fingerprint
  })

2. Use errors.Join for Better UX (Go 1.20)

• File: cmd/serve.go:71-85
• Change: Collect all flag validation errors and report together
• Benefit: Users see ALL missing required flags at once instead of one at a time
• Before: Sequential checks with immediate fatal on first error
• After:

  var errs []error
  if err := serveCmd.MarkFlagRequired("ldap-read-user"); err != nil {
      errs = append(errs, err)
  }
  // ... collect all errors
  if err := errors.Join(errs...); err != nil {
      log.Fatalln(err)
  }

3. Fix Incorrect Map Initialization

• Files: internal/server/route_ssh_key.go:230, 307
• Issue: make(map[...], 0) - maps don't accept capacity parameter
• Fix: Removed incorrect capacity parameter

4. Complete Type Safety - Replace ALL Untyped JSON

• Files: internal/server/route_ssh_key.go, internal/server/auth_middleware.go
• Added Types:

  // route_ssh_key.go
  type successResponse struct { Success bool }
  type keysResponse struct { Success bool; Keys map[string]models.SSHKey }
  type multiUserKeysResponse struct { Success bool; Keys map[string]map[string]models.SSHKey }
  type keyResponse struct { Success bool; Key *models.SSHKey }
  
  // auth_middleware.go
  type errorResponse struct { Success bool; Error string }

• Changed: All 13 handler/middleware functions that used map[string]interface{}
• Locations:
  • ✅ 11 route handlers in route_ssh_key.go
  • ✅ 2 middleware error responses in auth_middleware.go (initially missed!)

Features Analyzed But Not Applicable

Go Built-ins/Stdlib

• min/max (1.21) - No comparison logic that would benefit
• clear() (1.21) - No map/slice clearing patterns in codebase
• maps package (1.21) - No map cloning or comparison operations
• cmp package (1.21) - No complex comparison logic
• context.WithCancelCause (1.20) - No context usage at all in this codebase
• range over integers (1.22) - No numeric loop patterns
• Iterators (1.23) - No custom iteration patterns

Rationale

This is a simple REST API service with straightforward CRUD operations. Advanced features like context cancellation, iterators, and complex comparisons aren't needed for the current architecture.

Testing

• ✅ All existing unit tests pass
• ✅ go vet ./... clean
• ✅ gofmt compliant
• ✅ go build successful
• ✅ No breaking changes to API responses (backward compatible)

Performance & Quality Impact

• Performance: slices.DeleteFunc uses optimized stdlib implementation
• Type Safety: Compile-time checking prevents entire class of runtime errors
• User Experience: errors.Join shows all CLI errors at once
• Code Quality: Follows modern Go idioms from 1.20-1.25
• Maintainability: Typed responses easier to refactor and extend

Commits

1. 6565293 - Initial modernization (slices, typed routes, map fixes)
2. 1c0e814 - Complete pass (errors.Join, typed middleware, comprehensive analysis)

Verification

# Run tests
go test -v ./...

# Check code quality  
go vet ./...
gofmt -l .

# Build verification
go build -o /dev/null ./...

All checks pass successfully. Comprehensive Go 1.19 → 1.25 modernization complete.

🤖 Generated with Claude Code