Harden settings errors and show package version

[thebuilder]

Summary

• replace the misleading administrator-only load failure with status-aware, actionable recovery guidance
• preserve useful validation details for save failures and show connection-test failures locally
• centralize SDK and transport error decoding behind one typed API boundary
• display the installed Web Analytics package version at the bottom of Settings

Why

A client/server package mismatch could make the management APIs return 404 while the dashboard reported that administrator access was required. That hid the actual recovery path and made installation problems difficult to diagnose.

The dashboard now distinguishes expired sessions, missing permissions, missing endpoints, throttling, server failures, and network failures. In particular, a 404 explains that the server and backoffice package files may be out of sync and recommends restarting Umbraco and refreshing the backoffice.

Impact

Administrators get error messages that reflect the actual failure and include an appropriate next action. Unsaved settings remain intact after failed saves, connection-test failures stay attached to the relevant connection, and the installed package version is visible for support and troubleshooting.

Verification

• corepack pnpm check
• corepack pnpm build
• corepack pnpm test — 194 tests passed
• manually booted the Umbraco 17.4 example host with its SQLite database for visual verification