Add Linear as a source in "Import tickets"

SUMMARY Add Linear as a fourth source in "Import tickets", next to GitHub Issues, JIRA and Notion. Let a user connect more than one Linear workspace, and pick tickets assigned to them, filtered by status and project.

THE PROBLEM Many teams track their work in Linear, not in GitHub Issues or JIRA. Today, someone who works from Linear has to copy each issue into the backlog by hand before an agent can run it. That is slow, it drifts out of date and it loses context.

This hurts consultants and agencies the most. They often work for several clients at once, and each client has its own Linear workspace. They need to see "what's assigned to me" in every client's workspace without logging in and out.

PROPOSED BEHAVIOR

1. Connect Linear

• New source in the Import tickets picker: Linear.
• Auth: paste a Linear personal API key, read-only access. OAuth could come later.
• Store the key the same way other sources do: encrypted on the machine, never uploaded.

1. Multiple Linear accounts / workspaces

• A Linear API key belongs to one workspace, so each connection means one workspace.
• Let the user add several Linear connections, each with a label (for example "Acme", "Globex"), and show the workspace name and logo once it is connected.
• The import panel has a Workspace selector. Each project's saved query remembers which workspace it uses.
• On a machine where a workspace's key is missing, show the existing "Reconnect" badge, with the workspace named: "Linear (Acme) not connected".

1. Choose what to import

• "Assigned to me" checked by default.
• Team: one or more teams in the workspace.
• Project: one or more Linear projects, or "No project".
• Status: multi-select of the team's workflow states (Backlog, Todo, In Progress, In Review...). Also offer the state types (unstarted, started, completed, canceled), so one filter can work across team