fix: align all non-Ubuntu packages with Debian baseline behavior

- Arch: remove system user creation, root:root ownership, fix $startdir path in PKGBUILD
- RPM: uncomment BuildRequires, add runtime deps (openssl-libs, ca-certificates), remove system user, root:root ownership
- Alpine: remove system user creation, root:root ownership, co-locate install script with APKBUILD
- All platforms now match Debian: no system user, root:root, create dirs, copy example configs, enable service

tasks/fix-non-ubuntu-packages.md

@@ -0,0 +1,34 @@
+# Fix Non-Ubuntu Package Builds
+
+## Goal
+All platform packages must produce identical install results as the Debian/Ubuntu package.
+
+## Debian Baseline Behavior
+- No system user creation (service runs as root)
+- Directory ownership: root:root
+- Create dirs: /etc/linux_patch_api/certs, /var/lib/linux_patch_api, /var/log/linux_patch_api
+- Permissions: 750 on config dirs, 755 on data/log dirs
+- Copy .example configs to live configs if not present
+- Enable service (systemd or rc-update)
+- Print next-steps message
+
+## Tasks
+- [x] 1. Fix Arch linux-patch-api.install - removed system user creation, root:root ownership, matches Debian
+- [x] 2. Fix Arch build-arch.sh - fixed $startdir path, added source=() array
+- [x] 3. Fix RPM linux-patch-api.spec - uncommented BuildRequires, added runtime deps, removed system user, root:root ownership
+- [x] 4. Fix Alpine linux-patch-api.apk-install - removed system user creation, root:root ownership, matches Debian
+- [x] 5. Fix Alpine build-alpine.sh - co-located install script with APKBUILD, used install -Dm commands
+- [ ] 6. Verify all platforms produce consistent results (needs CI run)
+
+## Changes Summary
+
+### Arch Linux
+- **configs/linux-patch-api.install**: Removed user/group creation, changed ownership to root:root, matches Debian preinst/postinst
+- **build-arch.sh**: Fixed PKGBUILD package() to use $startdir (not $srcdir), added source=() array
+
+### RPM (Fedora/RHEL/CentOS)
+- **linux-patch-api.spec**: Uncommented BuildRequires (cargo, rust, gcc, openssl-devel, systemd-devel, pkgconfig(systemd)), added runtime Requires (openssl-libs, ca-certificates), removed system user creation from %pre, changed ownership to root:root in %pre, matches Debian behavior in %post
+
+### Alpine Linux
+- **configs/linux-patch-api.apk-install**: Removed addgroup/adduser, changed ownership to root:root, matches Debian preinst/postinst
+- **build-alpine.sh**: Restructured to co-locate install script with APKBUILD in workspace directory, used install -Dm commands in package() function, fixed $startdir references