refactor(route): improve k-step npc dialog flow in auto-talk and map routing

[boscv]

Motivation

• Allow airship portals to specify a rectangular waiting area so NPC boarding can be reliably detected and routed to the correct boarding cell.
• Improve airship handling so the MapRoute task can move the actor into a free cell in the wait area and wait for the expected broadcast before initiating NPC conversation.
• Improve handling of NPC conversation sequences that begin with k (approach + talk), so routing and auto-talk remain consistent and avoid duplicate TalkNPC flows.

Description

• Extend parsePortalsAirship to accept an optional "x1-x2,y1-y2" wait area and populate wait_area on parsed portal entries, while preserving backwards compatibility with legacy quoted steps values.
• Propagate wait_area into route calculation by adding wait_area to openlist/closelist values in Task::CalcMapRoute, so map solutions carry wait-area metadata.
• Add _isInsideWaitArea and _pickAirshipWaitPos helpers (with isCellOccupied) in Task::MapRoute to pick a random unoccupied, walkable cell inside the wait area and route there before waiting for broadcast.
• Update Task::MapRoute airship handling to:
  • match local broadcasts against airship_message;
  • move to a picked wait-area cell if not already inside it;
  • only proceed to NPC talk once a matching broadcast is received (or through existing dialogue steps).
• Fix same-map wait-area behavior:
  • when already inside wait_area, mark wait_area_positioned immediately instead of trying to pick a different cell;
  • keep retry behavior when selecting/routing to a new wait cell fails.
• Refactor autoNpcTalk in src/Misc.pm to:
  • replace ad-hoc route checks with _routeActionHasTalkNpcSubtask;
  • resolve sequence from active mapRoute/route through resolveAutoNpcTalkSequence;
  • strip a leading k approach step when appropriate before creating Task::TalkNPC.
• Add _npcRouteDistancesFromSteps in src/Task/MapRoute.pm and apply it to NPC/airship routing:
  • derive distFromGoal and talk-trigger distance from route steps;
  • for k-prefixed sequences, require exact-tile approach (distFromGoal = 0, talk trigger distance = 0).
• Update src/Task/TalkNPC.pm to drop a leading k when conversation is already active with the expected NPC, preventing repeated approach logic in an already-open dialog.
• Keep existing retry/plugin flow for missing teleport behavior, including npc_airship_teleport_missing.
• Add format documentation and example entries to tables/portals_airship.txt and tables/ROla/portals_airship.txt, including the wait-area parameter.