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/view_state_machine.hpp

@@ -0,0 +1,65 @@
+// view_state_machine.hpp — Navigation state and transitions for the world map.
+// Extracted from WorldMap zoom/enter methods (Phase 6 of refactoring plan).
+// SRP — pure state machine, no rendering or input code.
+#pragma once
+
+#include "rendering/world_map/world_map_types.hpp"
+
+namespace wowee {
+namespace rendering {
+namespace world_map {
+
+/// Manages the current view level and transitions between views.
+class ViewStateMachine {
+public:
+    ViewLevel currentLevel() const { return level_; }
+    const TransitionState& transition() const { return transition_; }
+
+    int continentIdx() const { return continentIdx_; }
+    int currentZoneIdx() const { return currentIdx_; }
+    bool cosmicEnabled() const { return cosmicEnabled_; }
+
+    void setContinentIdx(int idx) { continentIdx_ = idx; }
+    void setCurrentZoneIdx(int idx) { currentIdx_ = idx; }
+    void setCosmicEnabled(bool enabled) { cosmicEnabled_ = enabled; }
+    void setLevel(ViewLevel level) { level_ = level; }
+
+    /// Result of a zoom/navigate operation.
+    struct ZoomResult {
+        bool changed = false;
+        ViewLevel newLevel = ViewLevel::ZONE;
+        int targetIdx = -1;   // zone index to load/composite
+    };
+
+    /// Attempt to zoom in. hoveredZoneIdx is the zone under the cursor (-1 if none).
+    /// playerZoneIdx is the zone the player is standing in (-1 if none).
+    ZoomResult zoomIn(int hoveredZoneIdx, int playerZoneIdx);
+
+    /// Attempt to zoom out one level.
+    ZoomResult zoomOut();
+
+    /// Navigate to world view. Returns the root/fallback continent index to composite.
+    ZoomResult enterWorldView();
+
+    /// Navigate to cosmic view.
+    ZoomResult enterCosmicView();
+
+    /// Navigate directly into a zone from continent view.
+    ZoomResult enterZone(int zoneIdx);
+
+    /// Advance transition animation. Returns true while animating.
+    bool updateTransition(float deltaTime);
+
+private:
+    void startTransition(ViewLevel from, ViewLevel to, float duration = 0.3f);
+
+    ViewLevel level_ = ViewLevel::CONTINENT;
+    TransitionState transition_;
+    int continentIdx_ = -1;
+    int currentIdx_ = -1;
+    bool cosmicEnabled_ = true;
+};
+
+} // namespace world_map
+} // namespace rendering
+} // namespace wowee