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/ui/action_bar_panel.cpp

@@ -11,6 +11,7 @@
 #include "ui/quest_log_screen.hpp"
 #include "ui/ui_colors.hpp"
 #include "core/application.hpp"
+#include "core/world_loader.hpp"
 #include "core/logger.hpp"
 #include "rendering/renderer.hpp"
 #include "rendering/vk_context.hpp"
@@ -611,13 +612,8 @@ void ActionBarPanel::renderActionBar(game::GameHandler& gameHandler,
                         }
                         // Fall back to continent name if zone unavailable
                         if (homeLocation.empty()) {
-                            switch (mapId) {
-                                case 0:   homeLocation = "Eastern Kingdoms"; break;
-                                case 1:   homeLocation = "Kalimdor"; break;
-                                case 530: homeLocation = "Outland"; break;
-                                case 571: homeLocation = "Northrend"; break;
-                                default:  homeLocation = "Unknown"; break;
-                            }
+                            const char* dn = core::WorldLoader::mapDisplayName(mapId);
+                            homeLocation = dn ? dn : "Unknown";
                         }
                         ImGui::TextColored(ImVec4(0.8f, 0.9f, 1.0f, 1.0f),
                                            "Home: %s", homeLocation.c_str());

src/ui/inventory_screen.cpp

@@ -3,6 +3,7 @@
 #include "ui/keybinding_manager.hpp"
 #include "game/game_handler.hpp"
 #include "core/application.hpp"
+#include "core/world_loader.hpp"
 #include "rendering/vk_context.hpp"
 #include "core/input.hpp"
 #include "rendering/character_preview.hpp"
@@ -2632,15 +2633,8 @@ void InventoryScreen::renderItemTooltip(const game::ItemDef& item, const game::I
                 homeLocation = gameHandler_->getWhoAreaName(zoneId);
             // Fall back to continent name if zone unavailable
             if (homeLocation.empty()) {
-                switch (mapId) {
-                    case 0:   homeLocation = "Eastern Kingdoms"; break;
-                    case 1:   homeLocation = "Kalimdor"; break;
-                    case 530: homeLocation = "Outland"; break;
-                    case 571: homeLocation = "Northrend"; break;
-                    case 13:  homeLocation = "Test"; break;
-                    case 169: homeLocation = "Emerald Dream"; break;
-                    default:  homeLocation = "Unknown"; break;
-                }
+                const char* dn = core::WorldLoader::mapDisplayName(mapId);
+                homeLocation = dn ? dn : "Unknown";
             }
             ImGui::TextColored(ImVec4(0.8f, 0.9f, 1.0f, 1.0f), "Home: %s", homeLocation.c_str());
         } else {