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>

include/rendering/world_map/zone_metadata.hpp

@@ -0,0 +1,37 @@
+// zone_metadata.hpp — Zone level ranges, faction data, and label formatting.
+// Extracted from WorldMap::initZoneMeta and inline label formatting
+// (Phase 4 of refactoring plan). DRY — formatLabel used by multiple layers.
+#pragma once
+
+#include "rendering/world_map/world_map_types.hpp"
+#include <string>
+#include <unordered_map>
+
+namespace wowee {
+namespace rendering {
+namespace world_map {
+
+class ZoneMetadata {
+public:
+    /// Initialize the zone metadata table (level ranges, factions).
+    void initialize();
+
+    /// Look up metadata for a zone by area name. Returns nullptr if not found.
+    const ZoneMeta* find(const std::string& areaName) const;
+
+    /// Format a zone label with level range and faction tag.
+    /// e.g. "Elwynn (1-10) [Alliance]"
+    static std::string formatLabel(const std::string& areaName,
+                                    const ZoneMeta* meta);
+
+    /// Format hover label with level range and bracket-tag for faction.
+    static std::string formatHoverLabel(const std::string& areaName,
+                                         const ZoneMeta* meta);
+
+private:
+    std::unordered_map<std::string, ZoneMeta> table_;
+};
+
+} // namespace world_map
+} // namespace rendering
+} // namespace wowee