Fix tool results visibility, dynamic system prompt, rebrand Galaxy AI to Galaxy

- Rewrite extract_system_prompt to dynamically include CWD, OS, shell, git,
  project rules, and tool usage guidance from request context
- Fix extract_tool_result_content and format_tool_call_result to properly
  handle Grep, FileGlobV2, and ApplyFileDiffs results (were returning empty
  'Tool completed successfully' strings - model never saw file lists)
- Rename all 'Galaxy AI' references to just 'Galaxy' (menu, window title,
  bundle names, plist, welcome text, about)
- Update smoke test with file visibility test prompt
- Suppress dead_code warnings on unused smoke test functions

app/src/root_view.rs

@@ -121,7 +121,7 @@ use galaxyui::{FocusContext, NextNewWindowsHasThisWindowsBoundsUponClose};
 #[cfg(target_family = "wasm")]
 use crate::auth::web_handoff::{WebHandoffEvent, WebHandoffView};
 
-const WINDOW_TITLE: &str = "Galaxy AI";
+const WINDOW_TITLE: &str = "Galaxy";
 
 lazy_static! {
     static ref FALLBACK_WINDOW_SIZE: Vector2F = vec2f(800.0, 600.0);