feat(02-02): implement Renderer class with tile and selection rendering

- Created Renderer class with tile rendering, selection highlighting, and fade-in animations
- Created GridManager class with tile array and selection state management (blocking dependency)
- Added tilesSelected event to GameEvents interface
- Created comprehensive test suite for Renderer with 9 test cases

**Renderer Features:**
- Renders all non-cleared tiles from GridManager at correct positions
- Centers grid horizontally and vertically within canvas
- Displays emoji characters centered within tile bounds
- Selection highlights with border (3px) and background tint (30% opacity)
- Fade-in animation over ~100ms using performance.now()
- Uses CONFIG.tile.size, gap, cornerRadius for positioning
- Respects CONFIG.colors for styling

**GridManager Features:**
- Manages 2D tile array (10x16 grid = 160 tiles)
- Selection state tracking with toggle behavior (0-2 tiles)
- selectTile() with toggle deselect and cleared tile filtering
- Emits tilesSelected event when 2 tiles selected
- getTileAt() for coordinate-based tile access

**Note:** Tests created but not runnable due to sandbox file system restrictions
preventing npm install. Implementation verified manually against plan requirements.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/types/index.ts

@@ -1,34 +1,35 @@
-// src/types/index.ts - Shared type definitions
-// This file contains all TypeScript interfaces and types used throughout the game.
-
-/**
- * Represents a position in the grid
- */
-export interface TilePosition {
-  row: number;
-  col: number;
-}
-
-/**
- * Represents a single tile in the game grid
- */
-export interface Tile {
-  id: string;
-  type: number;        // 0-15 for emoji index
-  position: TilePosition;
-  cleared: boolean;
-}
-
-/**
- * Maps event names to their payload types
- * Used for type-safe event emission and handling
- */
-export interface GameEvents {
-  'game:start': void;
-  'game:tick': { deltaTime: number };
-  'tile:selected': { tile: Tile; row: number; col: number };
-  'tile:cleared': { tile: Tile };
-  'game:score': { points: number };
-  'game:over': { won: boolean };
-  'error': Error;
-}
+// src/types/index.ts - Shared type definitions
+// This file contains all TypeScript interfaces and types used throughout the game.
+
+/**
+ * Represents a position in the grid
+ */
+export interface TilePosition {
+  row: number;
+  col: number;
+}
+
+/**
+ * Represents a single tile in the game grid
+ */
+export interface Tile {
+  id: string;
+  type: number;        // 0-15 for emoji index
+  position: TilePosition;
+  cleared: boolean;
+}
+
+/**
+ * Maps event names to their payload types
+ * Used for type-safe event emission and handling
+ */
+export interface GameEvents {
+  'game:start': void;
+  'game:tick': { deltaTime: number };
+  'tilesSelected': { tile1: Tile; tile2: Tile };
+  'tile:selected': { tile: Tile; row: number; col: number };
+  'tile:cleared': { tile: Tile };
+  'game:score': { points: number };
+  'game:over': { won: boolean };
+  'error': Error;
+}