refactor(lib_commands): drop super::* + glob in app_api + lib_commands root

Hotspot G final slice — replace cascade-imports in app_api/{core,
analysis,integration,remote,platform}.rs with explicit per-symbol
imports, and convert app_api/mod.rs from broad `pub(crate) use foo::*`
to a per-command list of every Tauri handler.

The remaining glob re-exports live only in lib_commands/mod.rs itself
— and those are deliberate: they flatten the explicitly-listed Tauri
commands one more level so lib.rs's `use lib_commands::*` keeps the
invoke_handler shape unchanged. Each level above is now explicit.

file_transfer.rs's `super::subsonic_wire_user_agent()` becomes
`crate::subsonic_wire_user_agent()` since the lib_commands cascade
no longer pulls lib.rs symbols into super scope.

`grep -rn 'use super::\*' src/lib_commands/` returns zero hits.
Behaviour-preserving.

src-tauri/src/lib_commands/app_api/platform.rs

@@ -1,6 +1,6 @@
 //! Native-window + WebKitGTK platform tweaks exposed as Tauri commands.
 
-use super::*;
+use tauri::Manager;
 
 /// Toggle native window decorations at runtime (Linux custom title bar opt-out).
 #[tauri::command]