style: Extract UI constants and refactor main view rendering (#30)

- [x] Add golangci-lint configuration with gocritic ifElseChain disabled
- [x] Rename error variables to avoid shadowing (createErr, watcherErr, watchErr, etc.)
- [x] Replace `interface{}` with `any` type alias throughout codebase
- [x] Add package-level documentation comments to all internal packages
- [x] Reorder struct fields alphabetically for consistency
- [x] Extract UI constants (terminal dimensions, column widths, colors) to constants.go
- [x] Refactor BubbleTeaUI main view rendering into smaller helper functions
- [x] Simplify nested conditionals and improve code clarity
- [x] Add `isForwardDisabled()` helper method to BubbleTeaUI
- [x] Update file permissions from 0644 to 0600 in config tests
- [x] Add `#nosec` comments and error suppression where appropriate
- [x] Improve test table struct field ordering for readability
- [x] Fix resource parsing in AddForward using strings.SplitN
- [x] Add comprehensive tests for new UI helper functions and constants

internal/ui/handlers_test.go

@@ -695,12 +695,12 @@ func TestHandleSelectorValidated(t *testing.T) {
 func TestHandlePortChecked(t *testing.T) {
 	tests := []struct {
 		name        string
-		available   bool
 		expectStep  AddWizardStep
+		available   bool
 		expectError bool
 	}{
-		{"port available", true, StepConfirmation, false},
-		{"port in use", false, StepEnterLocalPort, true},
+		{name: "port available", available: true, expectStep: StepConfirmation, expectError: false},
+		{name: "port in use", available: false, expectStep: StepEnterLocalPort, expectError: true},
 	}
 
 	for _, tt := range tests {