phsl / new-api

This patch standardises how all “model” (and related) `<Select>` components handle searching.

Highlights
• Added a shared helper `modelSelectFilter` to `helpers/utils.js` – performs case-insensitive  value-based matching, independent of ReactNode labels.
• Removed the temporary `helpers/selectFilter.js`; all components now import from the core helpers barrel.
• Updated Selects to use the new filter *and* set `autoClearSearchValue={false}` so the query text is preserved after a choice is made.

Affected components
• Channel editor (EditChannelModal) – channel type & model lists
• Tag editor (EditTagModal) – model list
• Token editor (EditTokenModal) – model-limit list
• Playground SettingsPanel – model selector

Benefits
✓ Consistent search behaviour across the app
✓ Better user experience when selecting multiple items
✓ Cleaner codebase with one canonical filter implementation