Refactor: modularize code into separate files with enhanced documentation

- Split paula.cpp and modplayer.cpp into separate compilation units
- Created config.h for centralized configuration constants
- Created types.h for type definitions and utility functions
- Added comprehensive comments throughout all files
- Improved code organization with clear section dividers
- Maintained all original functionality and logic

src/config.h

@@ -0,0 +1,32 @@
+// =================== Configuration Constants ===================
+// All configuration defines for TinyMOD in one central location
+
+#ifndef CONFIG_H
+#define CONFIG_H
+
+// === Audio Configuration ===
+#define NUM_SECONDS         (1000)       // Duration to play (in seconds)
+#define SAMPLE_RATE         (96000)      // Playback sample rate (Hz)
+#define FRAMES_PER_BUFFER   (0x10000)    // Audio buffer size (65536 frames)
+
+// === Paula Chip Emulation ===
+// These constants define the Amiga Paula chip parameters
+const int PAULARATE = 3740000;             // Paula chip master clock (~3.546895MHz DAC base clock)
+const int OUTRATE = 48000;                 // Output/playback rate (48KHz)
+const int OUTFPS = 50;                     // Frames per second (50Hz - PAL)
+
+// === Paula Ring Buffer ===
+const int PAULA_RBSIZE = 4096;             // Paula ring buffer (circular buffer) size
+const int PAULA_FIR_WIDTH = 512;           // Finite Impulse Response (FIR) filter width
+
+// === MOD Format Constants ===
+const int MOD_CHANNELS = 4;                // Standard MOD files have 4 channels
+const int MOD_SAMPLES = 32;                // Maximum 32 samples per MOD file
+const int MOD_PATTERNS = 128;              // Maximum 128 patterns per MOD file
+const int MOD_PATTERN_ROWS = 64;           // 64 rows per pattern
+const int MOD_PATTERN_SIZE = 1024;         // 1024 bytes per pattern
+
+// === Utility Macros ===
+#define cls()               printf("\033[H\033[J")  // ANSI escape codes to clear screen
+
+#endif // CONFIG_H