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/k8s/client.go

@@ -1,3 +1,14 @@
+// Package k8s provides Kubernetes client management, resource resolution,
+// and port-forwarding capabilities for kportal.
+//
+// Key components:
+//   - ClientPool: Thread-safe management of Kubernetes clients per context
+//   - ResourceResolver: Resolves pod/service/selector targets to actual pods
+//   - PortForwarder: Establishes and manages port-forward connections
+//   - Discovery: Provides resource discovery for the UI wizards
+//
+// The package handles automatic pod restart detection through re-resolution,
+// caching with 30-second TTL, and graceful connection management.
 package k8s
 
 import (
@@ -12,10 +23,10 @@ import (
 
 // ClientPool manages Kubernetes clients per context with thread-safe access.
 type ClientPool struct {
-	mu      sync.RWMutex
+	loader  clientcmd.ClientConfig
 	clients map[string]*kubernetes.Clientset
 	configs map[string]*rest.Config
-	loader  clientcmd.ClientConfig
+	mu      sync.RWMutex
 }
 
 // NewClientPool creates a new ClientPool instance.
@@ -51,8 +62,8 @@ func (p *ClientPool) GetClient(contextName string) (*kubernetes.Clientset, error
 	defer p.mu.Unlock()
 
 	// Double-check in case another goroutine created it while we waited
-	if client, exists := p.clients[contextName]; exists {
-		return client, nil
+	if cachedClient, ok := p.clients[contextName]; ok {
+		return cachedClient, nil
 	}
 
 	// Create new client
@@ -91,8 +102,8 @@ func (p *ClientPool) GetRestConfig(contextName string) (*rest.Config, error) {
 	defer p.mu.Unlock()
 
 	// Double-check in case another goroutine created it while we waited
-	if config, exists := p.configs[contextName]; exists {
-		return config, nil
+	if cachedConfig, ok := p.configs[contextName]; ok {
+		return cachedConfig, nil
 	}
 
 	// Create new config