[FEATURE]: Preset phrases for quick prompt insertion

[ponponon]

Feature hasn't been suggested before.

• I have verified this feature I'm about to request hasn't been suggested before.

Describe the enhancement you want to request

Related: #25817

I frequently type the same instructions across sessions (coding conventions, project context, common tasks). It would save a lot of repetitive typing to have a "presets" feature in the prompt input.

What I'd like:

1. A button in the prompt input toolbar that opens a list of saved presets
2. Clicking a preset inserts its text into the editor
3. Variable support (e.g. {date}, {file}) that resolves at insertion time
4. A simple UI to add, edit, delete, and reorder presets
5. Presets stored as a JSON config file (e.g. in the project or user config directory)

Why a new issue: I commented on #25817 offering a working implementation but haven't heard back. Opening a fresh issue to discuss whether this is something the team would accept as a PR.

I have a working implementation ready and happy to adjust based on feedback.

[github-actions]

This issue might be a duplicate of existing issues. Please check:

• [FEATURE]: Preset instructions system for reusable chat prompts #25817: Preset instructions system for reusable chat prompts — this is an open feature request covering very similar functionality (reusable/saved prompt presets for the chat input).

You mentioned in the issue that you already commented on #25817. It's generally preferable to continue the discussion there rather than opening a new issue, so maintainers can consolidate feedback and implementation discussion in one place. Please consider closing this issue and continuing on #25817 instead — or let a maintainer decide if a separate issue is warranted.

[ponponon]

@Hona Hi, could you take a look at this? I have a working implementation ready. Would appreciate any feedback on whether this aligns with the project's direction. Thanks!

[ponponon]

@Brendonovich Hi, could you take a look at this? I have a working implementation ready. Would appreciate any feedback on whether this aligns with the project's direction. Thanks!

[ponponon]

I've created a PR to address the issues mentioned in this issue:

PR #32007: fix(app): improve presets i18n, storage, and UI consistency

Changes made:

1. i18n Support: Added translations for all 18 languages
2. Storage Refactor: Migrated from localStorage to platform-aware persisted storage (desktop: local file, web: localStorage)
3. UI Fixes:
   • Fixed button styling (size=large, variant=primary) to match project conventions
   • Fixed dialog padding to prevent content clipping
   • Replaced raw <input>/<textarea> with TextField component for consistent border styling
4. Testing: Added unit tests and i18n parity tests

The PR is ready for review.