Release pipeline after PhotoCraft's: AppImage/deb/rpm/Flatpak/tar.gz for Linux x86_64 and aarch64, FreeBSD, a macOS dmg and CLI zip, Windows x64/x86/arm64 MSI and portable zip (plus the plain x64 exe), web zip, SHA256SUMS.txt; version 0.1.2

Adapted from storytold/photocraft's release.yml and packaging/ (Apache-2.0; ATTRIBUTION.md and
NOTICE say so). Packages install the licence files, THIRD-PARTY-LICENSES.txt included. The app
icon is drawn by `solvecraft-cli icon` (a blue block with a bore, rendered on a transparent
background; .ico too), so no image is committed. Notes: a short header plus GitHub's generated
What's Changed. A dry run (Run workflow, publish off) keeps the files as the release-assets
artifact. packaging-lint.yml checks the workflows, scripts and metadata.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packaging/linux/postinst.sh

@@ -0,0 +1,13 @@
+#!/bin/sh
+# deb/rpm post-install and post-remove: refresh the desktop, MIME and icon caches.
+# Every tool is optional; missing ones are skipped.
+if command -v update-desktop-database >/dev/null 2>&1; then
+  update-desktop-database -q /usr/share/applications || true
+fi
+if command -v update-mime-database >/dev/null 2>&1; then
+  update-mime-database /usr/share/mime || true
+fi
+if command -v gtk-update-icon-cache >/dev/null 2>&1; then
+  gtk-update-icon-cache -q -t -f /usr/share/icons/hicolor || true
+fi
+exit 0