Guided remote-target setup: detect mounted volumes, handle SSH keys, use folder pickers

[jss367]

Problem

Setting up a remote target so that chained import → process → move-to-NAS works requires the user to complete three separate things, and only one of them exists in the UI:

1. The form — nine fields, six of which are typed absolute paths or SSH connection details.
2. SSH key setup — generating a keypair and installing it on the NAS (ssh-keygen + ssh-copy-id). Nothing in the app mentions this; the only signal is a failed connection test.
3. A GNU rsync install — a Homebrew package on macOS (see the rsync hint issue).

A walkthrough of a real first-time setup hit all three, plus two smaller snags (no save affordance, an unvalidated archive root that failed later with a message blaming a different field).

Observation motivating this

Of the nine form fields, essentially all were mechanically discoverable from the machine:

Field	Discoverable from
User	the SMB mount (//julius_admin@10.x.x.x/Photography)
Host	reverse lookup / Tailscale MagicDNS name for the mount's IP
Port	probe 22
Remote path	Synology convention /volume1/<share>, verifiable over SSH once connected
Local mount path	the mount table
Name	derivable from the share name
Port / bandwidth	sane defaults

The only genuinely user-supplied secret was the NAS password, needed once for ssh-copy-id.

Proposal

An "Add from mounted volume…" flow that:

1. Lists currently-mounted network volumes (SMB/AFP/NFS) with their server and share.
2. Pre-fills name, user, host, mount path, and a best-guess remote path from vendor conventions.
3. Detects whether an SSH key exists; offers to generate one if not.
4. Prompts once for the NAS password to install the key (equivalent of ssh-copy-id), so the user never sees a terminal.
5. Verifies the remote path over SSH and offers alternatives if the guess is wrong (ls -d /volume*/<share>).
6. Checks GNU rsync availability and surfaces the install command if missing.
7. Ends on a green connection test.

Also: replace typed absolute paths with folder pickers

Independently of the wizard, the path fields should be pickers:

• Local mount path and Local archive root in the remote-target form
• Destination on the Import page

These fields are currently too narrow to display a typical absolute path, which actively hides typos — a space-vs-underscore mismatch in an archive root went unnoticed through several screenshots because the visible text was truncated to /Users/julius/Pictures/Virec…. A picker makes that class of error structurally impossible, and would have prevented the archive-root issue outright.

Scope note

This is deliberately written as one umbrella issue because the pieces share a user journey, but they're independently shippable — the folder pickers and the mounted-volume prefill deliver most of the value without the SSH automation, which is the largest and riskiest part.

[jss367]

Related friction points from the same setup walkthrough, filed separately:

• Settings page auto-saves with no visible confirmation #1376 — Settings auto-saves with no visible confirmation
• Test connection reports OK when local_archive_root does not exist; Import then blames the destination #1377 — Test connection reports OK when local_archive_root doesn't exist (the folder-picker part of this issue would prevent it)
• Make the missing-GNU-rsync hint platform-specific and actionable #1378 — the missing-GNU-rsync hint could name the exact install command

Each is independently fixable; this issue is the umbrella for the end-to-end experience.