launch: accept config.phase_teams as a valid team source

Missions created via the new multi-team wizard have neither team_id
nor team_template_id set — they carry config.phase_teams. Both the
frontend Launch button gate and the backend set_status precondition
were checking only the old two fields, disabling launch for every
new wizard-created mission with a "No team" tooltip.

  - MissionCanvas: hasTeam now also returns true when
    mission.config.phase_teams has at least one non-empty list.
  - routes::missions::set_status: same check on the server so a
    direct API caller with only config.phase_teams also gets past
    the gate.

Directly unblocks the "we just finished the wizard, Launch is greyed
out" report. Agents materialize AFTER Launch — the button is the
trigger, not a post-condition of creation.

frontend/src/components/dashboard/MissionCanvas.tsx

@@ -411,8 +411,21 @@ export function MissionCanvas({
               <RefreshCw size={13} />
             </button>
             {mission.status === "draft" && (() => {
+              // Launch is enabled when we have SOMETHING that can
+              // materialize agents:
+              //   - team_id set (already materialized)
+              //   - team_template_id set (legacy single-team path)
+              //   - config.phase_teams has entries (new multi-team wizard path)
+              const phaseTeams =
+                (mission.config as { phase_teams?: Record<string, string[]> })
+                  ?.phase_teams;
+              const hasPhaseTeams =
+                phaseTeams &&
+                Object.values(phaseTeams).some((arr) => arr.length > 0);
               const hasTeam =
-                mission.team_id !== null || mission.team_template_id !== null;
+                mission.team_id !== null ||
+                mission.team_template_id !== null ||
+                Boolean(hasPhaseTeams);
               const disabled = launching || !hasTeam;
               return (
                 <button