feat(dees-geo-map): Highlight current navigation step with progress, mark completed steps, auto-scroll turn-by-turn list, expose guidance state for synchronization, and refine instruction/voice wording

ts_web/elements/00group-map/dees-geo-map/geo-map.voice.ts

@@ -291,12 +291,14 @@ export class VoiceSynthesisManager {
 
   /**
    * Speak approach maneuver instruction
-   * "In [distance], [maneuver] onto [street]"
+   * "In [distance], [maneuver] on/onto [street]"
    */
   public speakApproach(distance: string, maneuver: string, streetName?: string): void {
     let text = `In ${distance}, ${maneuver}`;
     if (streetName && streetName !== 'unnamed road') {
-      text += ` onto ${streetName}`;
+      // Use "on" for continue, "onto" for turns/merges
+      const preposition = maneuver.startsWith('continue') ? 'on' : 'onto';
+      text += ` ${preposition} ${streetName}`;
     }
     this.speak(text);
   }