start Databricks sign-in when saving provider setup

[morgmart]

Overview

Category: fix
User Impact: Databricks users with an existing OAuth credential stay recognized, and users completing setup can save workspace details and sign in through one Berd-native flow.
Problem: Goose setup-catalog data replaced the same-id curated databricks_v2 entry, dropping Berd identity and capability metadata. That hid the stored provider_cache:databricks OAuth credential, excluded Databricks from model refresh, and removed the native sign-in action. Save also stopped after host persistence and left terminal-oriented guidance. Solution: Fetched setup data now augments curated aliases and native-connect capability before runtime composition. Save then persists changed setup fields first and starts the existing backend-owned authentication flow when no token is entered; entering an access token continues to save directly without OAuth.

Changes

File changes

src/features/providers/api/catalog.ts
Composes fetched setup data with stable curated aliases and native-connect capability, and preserves the complete Databricks host-and-token field set.

src/features/providers/api/catalog.test.ts
Protects curated alias augmentation and the host-and-token setup field contract.

src/features/providers/runtimeProviderConfig.ts
Keeps setup-catalog fields for unmanaged Databricks providers while continuing to hide them when a managed endpoint is injected.

src/features/providers/runtimeProviderConfig.test.ts
Covers the fetched setup to runtime catalog boundary, including recognition of the shared databricks OAuth cache alias and model-refresh eligibility, plus managed and unmanaged field behavior.

src/features/providers/ui/ModelProviderRow.tsx
Sequences changed-field persistence before native authentication, starts authentication even when the host is already saved, and routes startup failures into the existing model setup state.

src/features/settings/ui/ModelProviderPanels.tsx
Shows authentication progress, streamed output, and failures inside the existing field-backed setup row while disabling edits during the operation.

src/features/settings/ui/tests/ModelProviderRow.test.tsx
Adds regressions for changed host plus OAuth, saved host plus OAuth, token save without OAuth, and authentication failure; existing API-key provider coverage remains intact.

src/shared/i18n/locales/en/settings.json
Replaces terminal setup instructions with Berd-native Save and sign-in guidance.

src/shared/i18n/locales/es/settings.json
Updates the matching Spanish guidance.

Validation

• just check
• Focused provider and Save regressions: 60 passed
• just test: 6,722 passed and 1 skipped; the one failure is the unchanged local telemetry session-store test under jsdom, which passed in the prior PR CI run