CI: Add fixes for tagged release runs and assorted minor issues

* Add provisioning profile support for macOS builds
* Fix internal variable names in macOS packaging script
* Add fallback git reference for validator actions
* Add required repository environment to documention deployment jobs
* Pass GitHub pull request number to GitHub CLI explicitly
* Use shortened commit hash for Steam nightly versions
* Ensure that concurrency check for tagged push uses a boolean value
* Update disk image creation function to retry ejection on CI
* Fix repository checkout in Flatpak publish action
* Fix output paths and filenames of generated appcast XML files
* Limit notice about notarization password use to non-CI usage
* Remove architecture-specific suffix from appcast artifact name

.github/scripts/utils.zsh/create_diskimage

@@ -1,4 +1,4 @@
-autoload -Uz log_debug log_error log_info log_status log_group log_output
+autoload -Uz log_debug log_error log_info log_status log_group log_output log_warning
 
 local -r _usage="Usage: %B${0}%b <source> <volume name> <output_name>
 
@@ -19,7 +19,7 @@ log_group "Create macOS disk image"
 local _hdiutil_flags
 if (( _loglevel < 1 )) _hdiutil_flags='-quiet'
 
-trap "hdiutil detach ${_hdiutil_flags} /Volumes/${output_name}; rm temp.dmg; log_group return 2" ERR
+trap "hdiutil detach ${_hdiutil_flags} /Volumes/${output_name}; rm temp.dmg; log_group; return 2" ERR
 
 hdiutil create ${_hdiutil_flags} \
     -volname "${volume_name}" \
@@ -47,7 +47,28 @@ chmod -Rf go-w /Volumes/${output_name}
 SetFile -a C /Volumes/${output_name}
 rm -rf -- /Volumes/${output_name}/.fseventsd(N)
 log_info "Converting disk image..."
-hdiutil detach ${_hdiutil_flags} /Volumes/${output_name}
+
+if (( ${+CI} )) {
+    local _status=0
+    for i ({1..5}) {
+        hdiutil detach ${_hdiutil_flags} /Volumes/${output_name} && _status=0 || _status=1
+
+        if (( status )) {
+            log_warning "Unable to eject disk image (attempt #${i}). Retrying."
+        } else {
+            break
+        }
+    }
+
+    if (( status )) {
+        log_error "Unable to eject disk image after 5 attempts. Aborting"
+        log_group
+        return 2
+    }
+} else {
+    hdiutil detach ${_hdiutil_flags} /Volumes/${output_name}
+}
+
 hdiutil convert ${_hdiutil_flags} \
     -format ULMO \
     -ov \