ui: Sidebar Conversations Bulk Action + Improved Settings logic/UI (#25815)

ui: Sidebar Conversations Bulk Action + Improved Settings logic/UI (#25815)

* feat: WIP

* feat: Replace conversation rename flow with unified AlertDialog component

* feat: Add radio group component and consolidate title generation settings

* refactor: Remove JS Sandbox global toggle and migrate legacy user state

* chore: Formatting

* refactor: Cleanup

Co-authored-by: Aleksander Grygier <redacted>
* refactor: Cleanup

* refactor: Marquee selection hook

* feat: UI improvements

* refactor: Bulk db operations

* fix: optimize bulk conversation deletion to handle ancestor chains

* refactor: remove pairedKey mechanism from settings system

* fix: remove redundant onclick handler from dialog cancel button

* chore: pin @lucide/svelte to exact version

* feat: Run JavaScript tool disabled by default

* fix: correct active conversation deletion tracking in bulk delete

* feat: improve shift-key multi-selection support in sidebar via keyboard

* refactor: Retrieve JS Tool enabling via Developer Settings

* nits: sync, dialog wording, cycle guard, and lockfile follow-ups

- Restore titleGenerationUseLLM registry entry so it syncs across devices again
- Mention fork cascade in the bulk delete confirmation dialog
- Clear newParent on cycle guard break so children never point at a deleted conversation
- Align @lucide/svelte in package-lock.json with the exact pin in package.json

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Co-authored-by: Pascal <redacted>