feat: Complete 2D Visual Overhaul - Isometric to Flat Top-Down

- NEW: Flat2DTerrainSystem.js (375 lines)
- NEW: map2d_data.js procedural map (221 lines)
- MODIFIED: GameScene async create, 2D terrain integration
- MODIFIED: Player.js flat 2D positioning
- MODIFIED: game.js disabled pixelArt for smooth rendering
- FIXED: 15+ bugs (updateCulling, isometric conversions, grid lines)
- ADDED: Phase 28 to TASKS.md
- DOCS: DNEVNIK.md session summary

Result: Working flat 2D game with Stardew Valley style!
Time: 5.5 hours

docs/HEIGHT_SYSTEM_PLAN.md

@@ -0,0 +1,102 @@
+# 🏔️ HEIGHT SYSTEM & 2.5D TERRAIN IMPLEMENTATION PLAN
+
+## 📋 OVERVIEW
+
+Transforming flat pixel-art terrain into 2.5D with procedural hills and elevation.
+
+---
+
+## 🎯 PHASE 1: HEIGHT GENERATION (IMPLEMENTING NOW)
+
+### Changes:
+1. **Add height property to tiles** (already exists in terrainTypes)
+2. **Generate height using 2nd Perlin noise layer**
+3. **Visual height representation:**
+   - Tint (darker = lower, lighter = higher)
+   - Scale (higher tiles = slightly bigger)
+   - Y-offset (elevation visual)
+
+### Code Changes:
+
+**TerrainSystem.js - generateChunk():**
+```javascript
+// NEW: Height noise (separate from terrain type noise)
+const heightNoise = this.noise.noise(x * 0.05, y * 0.05);
+const elevationHeight = Math.floor((heightNoise + 1) * 2.5); // 0-5 range
+
+// Store height in tile
+this.tiles[y][x] = {
+    type: tileType,
+    height: elevationHeight, // NEW!
+    solid: false
+};
+```
+
+**TerrainSystem.js - updateCulling() rendering:**
+```javascript
+// Apply visual height effects
+const tile = this.tiles[y][x];
+const height = tile.height || 0;
+
+// 1. Tint (darker low, lighter high)
+const tintValue = 0xffffff - (height * 0x111111);
+sprite.setTint(tintValue);
+
+// 2. Scale (subtle)
+const scaleBonus = 1 + (height * 0.02);
+sprite.setScale(scaleBonus);
+
+// 3. Y-offset (elevation)
+const yOffset = -(height * 4);
+sprite.y += yOffset;
+```
+
+---
+
+## 🎨 VISUAL RESULTS:
+
+```
+Before (Flat):
+████████████
+████████████
+████████████
+
+After (Hills):
+    ▓▓▓▓        ← Height 4 (lighter, higher)
+  ▒▒▒▒▒▒▒▒      ← Height 3
+░░░░░░░░░░░░    ← Height 2
+████████████    ← Height 0 (valleys, base)
+```
+
+---
+
+## 🚀 NEXT STEPS (PHASE 2):
+
+1. **Walkability constraints**
+   - Can't walk over height diff > 1
+   - Pathfinding with elevation
+
+2. **Smooth transitions**
+   - Slope tiles between heights
+   - Gradient blending
+
+3. **Cliff edges**
+   - Visual edge sprites
+   - Shadow effects
+
+---
+
+## 📊 CURRENT STATUS:
+
+- ✅ TerrainTypes have height property
+- ✅ Perlin noise available
+- ⏳ Height generation (implementing)
+- ⏳ Visual rendering (implementing)
+- ❌ Walkability (Phase 2)
+- ❌ Slope transitions (Phase 2)
+
+---
+
+**Implementation Date:** 2025-12-14  
+**Status:** In Progress  
+**Files Modified:** TerrainSystem.js