Magellan v2.2.5

• Version updated to 2.2.5 across core/desktop version files.
• Desktop now forces Setup Wizard once after each install/update/reinstall before normal use.
• Windows installer now writes an install marker used to trigger that per-install setup check.
• Onboarding now does real SQLite write probes to catch path/permission/disk I/O issues earlier.
• Desktop startup errors now include an Open Log action for faster diagnosis.
• Backend launch logic is more robust with better Python fallback selection and port allocation handling.
• Second-launch behavior was improved so the window can reopen correctly after browser handoff scenarios.
• Packaging now runs a packaged-backend smoke test as part of the desktop package flow.
• Python bundling for desktop was hardened (pip bootstrap fallback, Windows runtime copy, safer cleanup).
• File dialog support now includes an open file mode used by connect-to-existing-db flows.
• Onboarding UI text/flow was refined, including clearer admin-required messaging.
• Docs were updated with clearer setup/startup troubleshooting, logs guidance, and default credential notes.
• Regression tests were added/updated for packaging checks and onboarding install-gate behavior.