[FEATURE]: file upload, download and delete in the file manager

Feature request: file upload, download and delete in the file manager

• I have checked existing issues and feature requests and this is not a duplicate.

Problem

The web app's file browser currently only supports reading, listing and finding files. There is no way to add a file to a project from the browser, download a file to the local machine, or remove a file from the tree. Users have to resort to the terminal or an external editor.

Proposed solution

Add upload, download and delete actions across the file manager surfaces:

• Upload a file to the project directory from the session header, the file browser empty state, and the file manager panel (button picker + drag & drop).
• Download any file from the file tree, the search-results list, and the file manager panel.
• Delete a file or directory with an inline confirmation dialog.

Server/API

New endpoints in the server.fs group:

• GET /api/fs/download/* — streams a file as an attachment (raw bytes, so it is excluded from the generated client like fs.read).
• POST /api/fs/upload?path=...&location[directory]=... — base64 payload, returns 204.
• POST /api/fs/delete?path=...&location[directory]=... — returns 204.

Path containment is enforced on the server for all three operations (including symlink resolution for write/remove).

Client

The vendored SDK does not expose these operations yet, so the app calls the endpoints directly through a shared helper (packages/app/src/utils/file-transfer.ts), with Basic auth for remote servers and i18n labels for all supported locales.

Notes

• New i18n keys session.files.* added and translated in all 18 locales.
• Generated client files updated via bun run generate (the files group now exposes upload/delete).