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/exploration_state.hpp

@@ -0,0 +1,53 @@
+// exploration_state.hpp — Fog of war / exploration tracking (pure domain logic).
+// Extracted from WorldMap::updateExploration (Phase 3 of refactoring plan).
+// No rendering or GPU dependencies — fully testable standalone.
+#pragma once
+
+#include "rendering/world_map/world_map_types.hpp"
+#include <glm/glm.hpp>
+#include <unordered_map>
+#include <unordered_set>
+#include <vector>
+
+namespace wowee {
+namespace rendering {
+namespace world_map {
+
+class ExplorationState {
+public:
+    void setServerMask(const std::vector<uint32_t>& masks, bool hasData);
+    bool hasServerMask() const { return hasServerMask_; }
+
+    /// Recompute explored zones and overlays for given player position.
+    /// @param zones          All loaded zones
+    /// @param playerRenderPos Player position in render-space
+    /// @param currentZoneIdx  Currently viewed zone index
+    /// @param exploreFlagByAreaId  AreaID → ExploreFlag mapping from AreaTable.dbc
+    void update(const std::vector<Zone>& zones,
+                const glm::vec3& playerRenderPos,
+                int currentZoneIdx,
+                const std::unordered_map<uint32_t, uint32_t>& exploreFlagByAreaId);
+
+    const std::unordered_set<int>& exploredZones() const { return exploredZones_; }
+    const std::unordered_set<int>& exploredOverlays() const { return exploredOverlays_; }
+
+    /// Returns true if the explored overlay set changed since last update.
+    bool overlaysChanged() const { return overlaysChanged_; }
+
+    /// Clear accumulated local exploration data.
+    void clearLocal() { locallyExploredZones_.clear(); }
+
+private:
+    bool isBitSet(uint32_t bitIndex) const;
+
+    std::vector<uint32_t> serverMask_;
+    bool hasServerMask_ = false;
+    std::unordered_set<int> exploredZones_;
+    std::unordered_set<int> exploredOverlays_;
+    std::unordered_set<int> locallyExploredZones_;
+    bool overlaysChanged_ = false;
+};
+
+} // namespace world_map
+} // namespace rendering
+} // namespace wowee