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>

tests/test_world_map_zone_metadata.cpp

@@ -0,0 +1,86 @@
+// Tests for the extracted world map zone metadata module
+#include <catch_amalgamated.hpp>
+#include "rendering/world_map/zone_metadata.hpp"
+#include "rendering/world_map/world_map_types.hpp"
+
+#include <string>
+
+using namespace wowee::rendering::world_map;
+
+TEST_CASE("ZoneMetadata: find returns nullptr for unknown zone", "[world_map][zone_metadata]") {
+    ZoneMetadata zm;
+    zm.initialize();
+    REQUIRE(zm.find("NonexistentZoneXYZ") == nullptr);
+}
+
+TEST_CASE("ZoneMetadata: find returns valid data for known zones", "[world_map][zone_metadata]") {
+    ZoneMetadata zm;
+    zm.initialize();
+
+    const ZoneMeta* elwynn = zm.find("Elwynn");
+    REQUIRE(elwynn != nullptr);
+    REQUIRE(elwynn->minLevel > 0);
+    REQUIRE(elwynn->maxLevel >= elwynn->minLevel);
+    REQUIRE(elwynn->faction == ZoneFaction::Alliance);
+}
+
+TEST_CASE("ZoneMetadata: Contested zones", "[world_map][zone_metadata]") {
+    ZoneMetadata zm;
+    zm.initialize();
+
+    const ZoneMeta* sTV = zm.find("StranglethornVale");
+    REQUIRE(sTV != nullptr);
+    REQUIRE(sTV->faction == ZoneFaction::Contested);
+}
+
+TEST_CASE("ZoneMetadata: Horde zones", "[world_map][zone_metadata]") {
+    ZoneMetadata zm;
+    zm.initialize();
+
+    const ZoneMeta* durotar = zm.find("Durotar");
+    REQUIRE(durotar != nullptr);
+    REQUIRE(durotar->faction == ZoneFaction::Horde);
+}
+
+TEST_CASE("ZoneMetadata: formatLabel with no metadata", "[world_map][zone_metadata]") {
+    std::string label = ZoneMetadata::formatLabel("UnknownZone", nullptr);
+    REQUIRE(label == "UnknownZone");
+}
+
+TEST_CASE("ZoneMetadata: formatLabel with metadata", "[world_map][zone_metadata]") {
+    ZoneMeta meta;
+    meta.minLevel = 10;
+    meta.maxLevel = 20;
+    meta.faction = ZoneFaction::Alliance;
+
+    std::string label = ZoneMetadata::formatLabel("Elwynn", &meta);
+    // Should contain the zone name
+    REQUIRE(label.find("Elwynn") != std::string::npos);
+}
+
+TEST_CASE("ZoneMetadata: formatHoverLabel with metadata", "[world_map][zone_metadata]") {
+    ZoneMeta meta;
+    meta.minLevel = 30;
+    meta.maxLevel = 40;
+    meta.faction = ZoneFaction::Contested;
+
+    std::string label = ZoneMetadata::formatHoverLabel("StranglethornVale", &meta);
+    // Should contain both zone name and level range
+    REQUIRE(label.find("StranglethornVale") != std::string::npos);
+    REQUIRE(label.find("30") != std::string::npos);
+    REQUIRE(label.find("40") != std::string::npos);
+}
+
+TEST_CASE("ZoneMetadata: formatHoverLabel with no metadata just returns name", "[world_map][zone_metadata]") {
+    std::string label = ZoneMetadata::formatHoverLabel("UnknownZone", nullptr);
+    REQUIRE(label == "UnknownZone");
+}
+
+TEST_CASE("ZoneMetadata: double initialization is safe", "[world_map][zone_metadata]") {
+    ZoneMetadata zm;
+    zm.initialize();
+    zm.initialize();  // should not crash or change data
+
+    const ZoneMeta* elwynn = zm.find("Elwynn");
+    REQUIRE(elwynn != nullptr);
+}