feat: implement textured line clear effects and refine UI alignment

- **Visual Effects**: Upgraded line clear particles to use the game's block texture instead of simple circles, matching the reference web game's aesthetic.
- **Particle Physics**: Tuned particle velocity, gravity, and fade rates for a more dynamic explosion effect.
- **Rendering Integration**: Updated [main.cpp](cci:7://file:///d:/Sites/Work/tetris/src/main.cpp:0:0-0:0) and `GameRenderer` to pass the block texture to the effect system and correctly trigger animations upon line completion.
- **Menu UI**: Fixed [MenuState](cci:1://file:///d:/Sites/Work/tetris/src/states/MenuState.cpp:19:0-19:55) layout calculations to use fixed logical dimensions (1200x1000), ensuring consistent centering and alignment of the logo, buttons, and settings icon across different window sizes.
- **Code Cleanup**: Refactored `PlayingState` to delegate effect triggering to the rendering layer where correct screen coordinates are available.

src/gameplay/effects/LineEffect.h

@@ -0,0 +1,72 @@
+// LineEffect.h - Line clearing visual and audio effects
+#pragma once
+#include <SDL3/SDL.h>
+#include <vector>
+#include <random>
+
+class LineEffect {
+public:
+    struct Particle {
+        float x, y;
+        float vx, vy;
+        float size;
+        float alpha;
+        int blockType; // Added for textured particles
+        SDL_Color color;
+        
+        Particle(float px, float py);
+        void update();
+        void render(SDL_Renderer* renderer, SDL_Texture* blocksTex);
+        bool isAlive() const { return alpha > 0.0f; }
+    };
+
+    enum class AnimationState {
+        IDLE,
+        FLASH_WHITE,
+        EXPLODE_BLOCKS,
+        BLOCKS_DROP
+    };
+
+    LineEffect();
+    ~LineEffect();
+    
+    bool init(SDL_Renderer* renderer);
+    void shutdown();
+    
+    // Start line clear effect for the specified rows
+    void startLineClear(const std::vector<int>& rows, int gridX, int gridY, int blockSize);
+    
+    // Update and render the effect
+    bool update(float deltaTime); // Returns true if effect is complete
+    void render(SDL_Renderer* renderer, SDL_Texture* blocksTex, int gridX, int gridY, int blockSize);
+    
+    // Audio
+    void playLineClearSound(int lineCount);
+    
+    bool isActive() const { return state != AnimationState::IDLE; }
+
+private:
+    SDL_Renderer* renderer{nullptr};
+    AnimationState state{AnimationState::IDLE};
+    float timer{0.0f};
+    std::vector<int> clearingRows;
+    std::vector<Particle> particles;
+    std::mt19937 rng{std::random_device{}()};
+    
+    // Audio resources
+    SDL_AudioStream* audioStream{nullptr};
+    std::vector<int16_t> lineClearSample;
+    std::vector<int16_t> tetrisSample;
+    
+    // Animation timing - Flash then immediate explosion effect
+    static constexpr float FLASH_DURATION = 0.12f;   // Very brief white flash
+    static constexpr float EXPLODE_DURATION = 0.15f; // Quick explosive effect
+    static constexpr float DROP_DURATION = 0.05f;    // Almost instant block drop
+    
+    void createParticles(int row, int gridX, int gridY, int blockSize);
+    void updateParticles();
+    void renderFlash(int gridX, int gridY, int blockSize);
+    void renderExplosion(SDL_Texture* blocksTex);
+    bool loadAudioSample(const std::string& path, std::vector<int16_t>& sample);
+    void initAudio();
+};