refactor: decompose world map into modular component architecture

Break the monolithic 1360-line world_map.cpp into 16 focused modules
under src/rendering/world_map/:

Architecture:
- world_map_facade: public API composing all components (PIMPL)
- world_map_types: Vulkan-free domain types (Zone, ViewLevel, etc.)
- data_repository: DBC zone loading, ZMP pixel map, POI/overlay storage
- coordinate_projection: UV projection, zone/continent lookups
- composite_renderer: Vulkan tile pipeline + off-screen compositing
- exploration_state: server mask + local exploration tracking
- view_state_machine: COSMIC→WORLD→CONTINENT→ZONE navigation
- input_handler: keyboard/mouse input → InputAction mapping
- overlay_renderer: layer-based ImGui overlay system (OCP)
- map_resolver: cross-map navigation (Outland, Northrend, etc.)
- zone_metadata: level ranges and faction data

Overlay layers (each an IOverlayLayer):
- player_marker, party_dot, taxi_node, poi_marker, quest_poi,
  corpse_marker, zone_highlight, coordinate_display, subzone_tooltip

Fixes:
- Player marker no longer bleeds across continents (only shown when
  player is in a zone belonging to the displayed continent)
- Zone hover uses DBC-projected AABB rectangles (restored from
  original working behavior)
- Exploration overlay rendering for zone view subzones

Tests:
- 6 new test files covering coordinate projection, exploration state,
  map resolver, view state machine, zone metadata, and integration

Signed-off-by: Pavel Okhlopkov <pavel.okhlopkov@flant.com>

src/core/world_loader.cpp

@@ -71,6 +71,8 @@ const char* WorldLoader::mapDisplayName(uint32_t mapId) {
     switch (mapId) {
         case 0: return "Eastern Kingdoms";
         case 1: return "Kalimdor";
+        case 13: return "Test";
+        case 169: return "Emerald Dream";
         case 530: return "Outland";
         case 571: return "Northrend";
         default: return nullptr;
@@ -170,6 +172,15 @@ const char* WorldLoader::mapIdToName(uint32_t mapId) {
     }
 }
 
+int WorldLoader::mapNameToId(const std::string& name) {
+    // Reverse lookup: iterate known continent IDs and match against mapIdToName.
+    static constexpr uint32_t kContinentIds[] = {0, 1, 530, 571};
+    for (uint32_t id : kContinentIds) {
+        if (name == mapIdToName(id)) return static_cast<int>(id);
+    }
+    return -1;
+}
+
 void WorldLoader::processPendingEntry() {
     if (!pendingWorldEntry_ || loadingWorld_) return;
     auto entry = *pendingWorldEntry_;