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/bin/oss.rs

@@ -39,7 +39,7 @@ embed_plist::embed_info_plist_bytes!(r#"
     <key>CFBundleDevelopmentRegion</key>
     <string>English</string>
     <key>CFBundleDisplayName</key>
-    <string>Galaxy AI</string>
+    <string>Galaxy</string>
     <key>CFBundleExecutable</key>
     <string>galaxy-ai-oss</string>
     <key>CFBundleIdentifier</key>
@@ -47,7 +47,7 @@ embed_plist::embed_info_plist_bytes!(r#"
     <key>CFBundleInfoDictionaryVersion</key>
     <string>6.0</string>
     <key>CFBundleName</key>
-    <string>Galaxy AI</string>
+    <string>Galaxy</string>
     <key>CFBundlePackageType</key>
     <string>APPL</string>
     <key>CFBundleShortVersionString</key>
@@ -59,7 +59,7 @@ embed_plist::embed_info_plist_bytes!(r#"
     <key>UIDesignRequiresCompatibility</key>
     <true/>
     <key>CFBundleURLTypes</key>
-    <array><dict><key>CFBundleURLName</key><string>Galaxy AI</string><key>CFBundleURLSchemes</key><array><string>galaxyai</string></array></dict></array>
+    <array><dict><key>CFBundleURLName</key><string>Galaxy</string><key>CFBundleURLSchemes</key><array><string>galaxyai</string></array></dict></array>
     <key>NSHumanReadableCopyright</key>
     <string>© 2026, Samsung Electronics Co., Ltd.</string>
     </dict>