refactor(test): dissolve coverage_test.go into domain-specific test files

coverage_test.go was a catch-all that revealed a meta-goal ("coverage")
rather than the domain it tests. Distribute all 91 tests into files named
after what they test:

- keymap_test.go        (new): KeyBindingMap getter methods
- keystroke_test.go     (new): KeyStrokeKind.String, constructors, validate
- platform_test.go      (new): DetectTerminal, GetTerminalCapabilities,
                                GetPlatformSpecificKeyBindings,
                                GetTerminalSpecificKeyBindings
- context_manager_test.go: SetContext, ForceEnvironment, Animator tests
- profile_test.go:       GetAllProfiles/Contexts, IsValid, Clone, Validate,
                          GetProfileStatistics, CompareProfiles
- runtime_profile_switch_test.go: ProfileSwitcher, HandleProfileSwitchCommand
- features_test.go:      ToYAML (simple + extended), formatKeystrokeForExport,
                          Ke                          Ke                          Ke                          Ke                          Ke      rseUserBindingValue

Author: bmf-san

internal/keybindings/context_manager_test.go

@@ -2,6 +2,7 @@ package keybindings
 
 import (
 	"testing"
+	"time"
 
 	"github.com/bmf-san/ggc/v8/internal/config"
 )
@@ -60,3 +61,100 @@ func TestContextManagerStackAndCallbacks(t *testing.T) {
 		t.Fatalf("exit on empty stack returned %v", got)
 	}
 }
+
+// ── ContextManager: SetContext, ForceEnvironment ─────────────────────────────
+
+func TestContextManager_SetContext(t *testing.T) {
+	resolver := NewKeyBindingResolver(&config.Config{})
+	RegisterBuiltinProfiles(resolver)
+	cm := NewContextManager(resolver)
+
+	var transitions [][2]Context
+	cm.RegisterContextCallback(ContextResults, func(from, to Context) {
+		transitions = append(transitions, [2]Context{from, to})
+	})
+
+	// SetContext to new context
+	cm.SetContext(ContextResults)
+	if cm.GetCurrentContext() != ContextResults {
+		t.Errorf("SetContext: current = %v, want %v", cm.GetCurrentContext(), ContextResults)
+	}
+	if len(transitions) != 1 {
+		t.Errorf("expected 1 transition callback, got %d", len(transitions))
+	}
+
+	// SetContext to same context should be no-op
+	cm.SetContext(ContextResults)
+	if len(transitions) != 1 {
+		t.Errorf("SetContext same context should not fire callback, got %d transitions", len(transitions))
+	}
+
+	// Stack should be unmodified
+	if len(cm.GetContextStack()) != 0 {
+		t.Errorf("SetContext should not modify stack, got %v", cm.GetContextStack())
+	}
+}
+
+func TestContextManager_ForceEnvironment(t *testing.T) {
+	resolver := NewKeyBindingResolver(&config.Config{})
+	RegisterBuiltinProfiles(resolver)
+	cm := NewContextManager(resolver)
+
+	// Should not panic
+	cm.ForceEnvironment("darwin", "xterm-256color")
+}
+
+func TestContextManager_ForceEnvironment_NilCM(t *testing.T) {
+	var cm *ContextManager
+	// Should not panic
+	cm.ForceEnvironment("linux", "xterm")
+}
+
+// ── ContextTransitionAnimator ────────────────────────────────────────────────
+
+func TestContextTransitionAnimator_FadeAndSlide(t *testing.T) {
+	cta := NewContextTransitionAnimator()
+	cta.SetDuration(0) // no sleep in tests
+
+	cta.SetStyle("fade")
+	cta.AnimateTransition(ContextGlobal, ContextResults)
+
+	cta.SetStyle("slide")
+	cta.AnimateTransition(ContextGlobal, ContextInput)
+}
+
+func TestContextTransitionAnimator_Disable(t *testing.T) {
+	cta := NewContextTransitionAnimator()
+	cta.Disable()
+	// Should return early without doing anything
+	cta.AnimateTransition(ContextGlobal, ContextResults)
+	if cta.enabled {
+		t.Error("expected disabled animator")
+	}
+}
+
+func TestContextTransitionAnimator_Enable(t *testing.T) {
+	cta := NewContextTransitionAnimator()
+	cta.Disable()
+	cta.Enable()
+	if !cta.enabled {
+		t.Error("expected enabled animator")
+	}
+}
+
+func TestContextTransitionAnimator_RegisterAnimation(t *testing.T) {
+	cta := NewContextTransitionAnimator()
+	cta.RegisterAnimation(func(from, to Context) {})
+	cta.RegisterAnimation(func(from, to Context) {})
+	if len(cta.animations) != 2 {
+		t.Errorf("expected 2 registered animations, got %d", len(cta.animations))
+	}
+}
+
+func TestContextTransitionAnimator_SetDuration(t *testing.T) {
+	cta := NewContextTransitionAnimator()
+	cta.SetDuration(500 * time.Millisecond)
+	if cta.duration != 500*time.Millisecond {
+		t.Errorf("duration = %v, want 500ms", cta.duration)
+	}
+}