feat(mail): attach files from Frappe Drive in the composer

[krantheman]

Overview

Implements #46 — attach files from Frappe Drive while composing a mail.

The composer's paperclip becomes a small menu:

• Upload from computer — the existing local upload, unchanged.
• Attach from Frappe Drive — opens a Drive file picker.

What's included

• DriveFilePicker.vue (new modal): browses the user's Drive — team home with breadcrumb folder navigation, folders-first listing, and multi-select — backed by suite.drive.api.list.files (+ permissions.get_teams). A team selector appears only for multi-team users.
• ComposeMailToolbar.vue: the paperclip is now a Dropdown with the two attach options.
• ComposeMailEditor.vue: on Drive selection, each file's bytes are fetched via suite.drive.api.files.get_file_content (permission-checked server-side), wrapped as a File, and pushed through the existing upload pipeline (upload_file → attachDoc). A Drive attachment therefore becomes an ordinary Frappe File with a real file_url, and the send path (create_mail/update_draft_mail) needs no changes.

Scope matches the maintainer's note on #46: Frappe Drive only (no Google Drive etc.).

Design note

The "copy bytes" approach (fetch from Drive → re-upload through mail's upload_file) was chosen over teaching the mail backend to resolve a Drive entity_name, because a Drive file's file_url is a storage key that the mail queue can't read directly — Drive always serves bytes through permission-checked get_file_content. Reusing the proven attachment pipeline keeps the change frontend-only.

Testing

Compose a mail → paperclip → Attach from Frappe Drive → browse/select one or more files → Attach. The files appear as normal attachments and send with the mail. Verified end-to-end locally: select → get_file_content → upload_file → attachment chip in the composer.

🤖 Generated with Claude Code

[greptile-apps]

Confidence Score: 4/5

Safe to merge after fixing the team-change selection leak; the rest of the change is additive and reuses proven upload logic.

Switching teams in the picker silently carries over file selections from the previous team, causing unintended attachments. Everything else — the toolbar dropdown, breadcrumb navigation, Promise.allSettled fetch loop — looks correct.

DriveFilePicker.vue — specifically the onTeamChange handler.

_{Reviews (1): Last reviewed commit: "feat(mail): attach files from Frappe Dri..." | Re-trigger Greptile}

[greptile-apps]

onTeamChange resets the breadcrumbs and reloads the file list but never clears selected or selectedEntries. A user who selects files in Team A, switches to Team B, and clicks Attach silently re-attaches the Team A files — the counter still shows them and they are all emitted.

Suggested change

	const onTeamChange = () => {
	breadcrumbs.value = [{ name: null, label: __('Home') }]
	load()
	}
	const onTeamChange = () => {
	breadcrumbs.value = [{ name: null, label: __('Home') }]
	selected.value = new Set()
	selectedEntries.clear()
	load()
	}