refactor: deduplicate and consolidate extension install/update/uninstall system

[Copilot]

This pull request refactors the extension installation command to improve code reuse and maintainability by extracting the logic for resolving extension package sources into a shared trait. The main effect is to centralize and standardize how extension packages are resolved for both installation and update commands, reducing duplication and potential inconsistencies.

Key changes include:

Refactoring and Code Reuse

• Introduced a new trait HandlesExtensionPackages in app/Console/Commands/Extensions/Concerns/HandlesExtensionPackages.php, which encapsulates all logic for resolving extension package sources, handling user prompts, debug output, and ownership reporting. This trait is designed to be shared between install and update commands.
• Updated InstallExtensionCommand to use the new HandlesExtensionPackages trait, removing the previously duplicated resolution logic from this command. The command now calls resolveResolution from the trait instead of its own local method. [1] [2]

Code Cleanup

• Removed the now-redundant private methods (resolveInstallResolution, resolveFileModeSelection, selectDiscoveredArtifact, createFileResolution, renderDebugResolution, renderDebugException, renderOwnershipReport, and isDebug) from InstallExtensionCommand, as these are now provided by the trait.
• Updated the constructor for InstallExtensionCommand to remove the unused dependency on ExtensionPackageArtifactService, since artifact handling is now encapsulated in the trait.

These changes make the codebase more modular and easier to maintain, ensuring consistent behavior across extension-related commands.~540 lines of near-identical logic were duplicated across InstallService, UpdateService, and the three command classes. This extracts the shared code into proper shared services and a command trait, and fixes two silent bugs found during the audit.

Shared services introduced

• ExtensionPackageArtifactService — promoted from private helpers to public API: downloadArchive(), verifyChecksum(), extractArchive(), readPackageManifest(), normalizeManifest(), assertCompatiblePanelVersions(), normalizeTargetPath(). Also now owns PACKAGE_ARTIFACT_FILENAME constant (was duplicated in both install and update services).
• ExtensionPackageFileService — assertFilesUnmodified(), createRollbackSnapshot(), restoreRollbackSnapshot() extracted from uninstall/update services.

Commands consolidated

HandlesExtensionPackages trait absorbs what was ~270 lines of copy-pasted code in InstallExtensionCommand and UpdateExtensionCommand:

• resolveResolution() — repository vs. local-file mode selection with interactive fallback
• renderDebugResolution(), renderDebugException(), renderOwnershipReport(), isDebug()

Result: both commands shrink from ~358 lines to 87 lines each.

Bug fixes

• ExtensionPackageBatchService finally blocks were not calling repairStandardPaths() — root-run batch operations could leave paths with wrong ownership on failure.
• ExtensionInstallProgressService match defaulted unrecognised actions to UNINSTALL_STAGES silently. Now 'uninstall' is an explicit arm and unknown actions throw \InvalidArgumentException.
• ExtensionOperationLockService blocked-message builder replaced 20-line repetitive match with a single sprintf.

Line count delta (modified files only)

File	Before	After
ExtensionPackageInstallService	619	459
ExtensionPackageUpdateService	765	533
ExtensionPackageUninstallService	275	207
InstallExtensionCommand	357	87
UpdateExtensionCommand	358	87
New: ExtensionPackageArtifactService (expanded)	164	299
New: ExtensionPackageFileService	—	97
New: HandlesExtensionPackages trait	—	294