feat(desktop): add toggle to hide unconfigured providers in model picker

[brian717]

What

Adds an opt-in "Hide Unconfigured Providers" toggle to the Desktop model-picker footer (next to Edit Models). When enabled, the picker hides providers the user has no usable credentials for, so someone who only configured a couple of providers isn't scrolling past the entire catalog.

Resolves #59483.

Why

The picker lists every provider from the catalog, including canonical rows surfaced with a setup affordance that the user hasn't set up. The issue reporter (uses only DeepSeek) has to scroll past Anthropic, OpenAI, Google, OpenRouter, etc. every time.

The data needed already exists on the frontend; ModelOptionProvider.authenticated is "True when the provider has usable credentials", so no backend change is required.

Changes

• store/model-visibility.ts: new persisted $hideUnconfiguredProviders atom + setter (reuses the existing storedBoolean/persistBoolean storage pattern), and a pure filterConfiguredProviders(providers, hide, currentProviderSlug) helper.
• app/shell/model-menu-panel.tsx: reads the store, filters pickerProviders, and renders the toggle with a check mark when active.
• i18n: hideUnconfigured string added to en.ts, zh.ts, and types.ts.
• store/model-visibility.test.ts: 4 new unit tests for the filter helper.

Design notes

• Opt-in, default off — chosen over the issue's alternative "make it the default", which would change behavior for all users.
• Only an explicit authenticated === false is filtered; a missing flag is treated as configured (safe default for user/custom providers).
• The active provider is always kept visible, so the currently-selected model can never disappear from the picker.
• Setting persists across restarts via localStorage, matching the sibling model-visibility feature.

Testing

• vitest run on the affected suites: 26 passed (incl. 4 new).
• tsc --noEmit: clean.
• eslint on all changed files: clean.
• Manual: open the model picker → toggle Hide Unconfigured Providers → providers without credentials disappear (check appears); toggle again to restore; persists across restart.

Renderer typecheck/tests only; full desktop build (tsc -b + vite) not run.

[teknium1]

Thanks for the focused Desktop implementation. This is an automated hermes-sweeper review.

• Current main already implements the requested outcome through 37a4cf9000ce8e0da6017cbe8bb4a2e8617a7737 (fix: limit desktop model pickers to explicit providers), shipped in v2026.7.7.
• apps/desktop/src/lib/model-options.ts:13 defaults Desktop chat-picker requests to explicitOnly: true, and apps/desktop/src/lib/model-options.ts:30 sends explicit_only=true to the gateway.
• hermes_cli/inventory.py:111 applies the corresponding backend filter, keeping only explicitly configured providers.
• The merged PR fix: limit desktop model pickers to explicit providers (#56974) #60514 explicitly addressed the picker-clutter request in linked issue [Feature]: Filter model selector dropdown to only show providers with configured API keys #59483, which is now closed as implemented.

Closing as implemented on main; the current default behavior is stronger than the proposed opt-in toggle.