PROC: activate approach/missed/vector-to-final; DCLTR-2 declutters airspace

PROC menu actions were empty stubs. Now: procedures.js tags approach legs with
seg ('approach'|'missed' — everything past the runway threshold = missed,
previously dropped); Proc.jsx flags loaded legs appr/missed (preserved by
flightplan.setPlan) and the ACTIVATE APPROACH / MISSED APPROACH / VECTOR-TO-FINAL
items set the active (magenta) leg to the matching segment, with a hint when
nothing is loaded. Missed legs shown dimmed in the preview.

DCLTR-2 now hides the airspace (SUA) overlay, matching the manual (p.56), in
addition to the existing nav-symbol declutter.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/flightplan.js

@@ -18,7 +18,7 @@ export function setPlan(next) {
   const wps = Array.isArray(next?.waypoints)
     ? next.waypoints
         .filter((w) => isFinite(w.lat) && isFinite(w.lon))
-        .map((w) => ({ id: String(w.id || 'WPT'), lat: +w.lat, lon: +w.lon, type: w.type || 'WPT', alt: w.alt ?? null, ...(w.dsgn != null ? { dsgn: !!w.dsgn } : {}), ...(w.appr ? { appr: true } : {}) }))
+        .map((w) => ({ id: String(w.id || 'WPT'), lat: +w.lat, lon: +w.lon, type: w.type || 'WPT', alt: w.alt ?? null, ...(w.dsgn != null ? { dsgn: !!w.dsgn } : {}), ...(w.appr ? { appr: true } : {}), ...(w.missed ? { missed: true } : {}) }))
     : [];
   const wantLeg = Number.isFinite(next?.activeLeg) ? next.activeLeg : 1;
   plan = { name: next?.name || 'ACTIVE', waypoints: wps, activeLeg: Math.max(1, Math.min(wps.length - 1, wantLeg)) || 1 };