feat: add GotoTop/Bottom/PrevPage/NextPage navigation keys

- New global keybindings: GotoTop (Home), GotoBottom (G/End), PrevPage ([), NextPage (])
- Wired in history, findings, and intercept update handlers
- Removes duplicate tea.Quit case in intercept/update.go

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

internal/config/default_config.yaml

@@ -60,6 +60,10 @@ keybindings:
     scroll_up: "pgup"
     scroll_down: "pgdown"
     send_to_diff: "ctrl+d"
+    goto_top: "home"
+    goto_bottom: "G,end"
+    prev_page: "["
+    next_page: "]"
 
   intercept:
     forward: "f"

internal/config/keybindings.go

@@ -16,6 +16,10 @@ type GlobalKeys struct {
 	ScrollUp      string `mapstructure:"scroll_up"`
 	ScrollDown    string `mapstructure:"scroll_down"`
 	SendToDiff    string `mapstructure:"send_to_diff"`
+	GotoTop       string `mapstructure:"goto_top"`
+	GotoBottom    string `mapstructure:"goto_bottom"`
+	PrevPage      string `mapstructure:"prev_page"`
+	NextPage      string `mapstructure:"next_page"`
 }
 
 type InterceptKeys struct {