Update to version 3.0.21

Bump pkgver and sha256sums for devin-desktop 3.0.21. Drop stale
appdata/zsh mv lines from build() — no longer present in the deb.
Update updater to use dynamic deb_path from the Packages index,
remove .SRCINFO auto-update (now handled manually), reset pkgrel=1
on each bump, and switch build hint to paru -Bi. Add pkg/ to cleanup.

Generated with [Devin](https://cli.devin.ai/docs)

Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

.SRCINFO

@@ -1,6 +1,6 @@
 pkgbase = devin-desktop
 	pkgdesc = Devin - the AI software engineer IDE
-	pkgver = 2.3.15
+	pkgver = 3.0.21
 	pkgrel = 1
 	url = https://devin.ai/
 	arch = x86_64
@@ -23,11 +23,11 @@ pkgbase = devin-desktop
 	provides = windsurf
 	provides = devin-desktop
 	conflicts = windsurf
-	noextract = devin-desktop-2.3.15.deb
+	noextract = devin-desktop-3.0.21.deb
 	options = !strip
-	source = devin-desktop-2.3.15.deb::https://windsurf-stable.codeiumdata.com/wVxQEIWkwPUEAGf3/apt/pool/main/d/devin-desktop/Devin-linux-x64-2.3.15.deb
+	source = devin-desktop-3.0.21.deb::https://windsurf-stable.codeiumdata.com/wVxQEIWkwPUEAGf3/apt/pool/main/d/devin-desktop/Devin-linux-x64-3.0.21.deb
 	source = code.sh::https://gitlab.archlinux.org/archlinux/packaging/packages/code/-/raw/main/code.sh
-	sha256sums = bd740d4872aed1d56303e4d4342ec41f634fcc82bb1c12cd6c3e29546a0a13e6
-	sha256sums = bd740d4872aed1d56303e4d4342ec41f634fcc82bb1c12cd6c3e29546a0a13e6
+	sha256sums = 909fd19e4f7e7f3bee5f213607a6c302d50345f3c1d96090f1bb3ae19b1b8ee4
+	sha256sums = 5da1525b5fe804b9192c05e1cbf8d751d852e3717fb2787c7ffe98fd5d93e8c1
 
 pkgname = devin-desktop