refactor: collapse micro-modules, add AUR packaging

- domain/ (7 files) → domain.rs + error.rs + window.rs
- protocols/sftp/ (4 files) → sftp.rs, ftp/ (3 files) → ftp.rs
- storage/db/ (6 files) → storage.rs + settings.rs
- transfer/ (5 files) → transfers/{queue,worker}.rs
- add dist/PKGBUILD, .SRCINFO, wherry.desktop for AUR
- fix all import paths, 53 tests pass

dist/.SRCINFO

@@ -0,0 +1,22 @@
+pkgbase = wherry
+	pkgdesc = A modern dual-pane file manager with SFTP/FTP/FTPS support
+	pkgver = 0.1.0
+	pkgrel = 1
+	url = https://github.com/loki5512344/Wherry
+	install =
+	arch = x86_64
+	license = GPL3
+	makedepends = cargo
+	makedepends = rust
+	makedepends = patchelf
+	depends = webkit2gtk-4.1
+	depends = gtk3
+	depends = libsoup-3.0
+	depends = librsvg
+	depends = libappindicator-gtk3
+	depends = libdbus-1
+	depends = openssl
+	source = wherry-0.1.0.tar.gz::https://github.com/loki5512344/Wherry/archive/refs/tags/v0.1.0.tar.gz
+	sha256sums = SKIP
+
+pkgname = wherry