feat(gpu): Add parameter-driven ChromaAberrationEffect

Implements Task #73 - Extends shader parametrization system to
ChromaAberrationEffect following the FlashEffect pattern.

Changes:
- Added ChromaAberrationParams struct (offset_scale, angle)
- Added ChromaUniforms with proper WGSL alignment (32 bytes)
- Updated shader to compute offset direction from angle parameter
- Extended seq_compiler to parse offset/angle parameters
- Updated demo.seq with 2 parameterized instances:
  * Line 50: offset=0.03 angle=0.785 (45° diagonal, stronger)
  * Line 76: offset=0.01 angle=1.57 (90° vertical, subtle)

Technical details:
- Backward-compatible default constructor maintained
- Migrated from raw buffer to UniformBuffer<ChromaUniforms>
- Shader computes direction: vec2(cos(angle), sin(angle))
- Generated code creates ChromaAberrationParams initialization

Testing:
- All 32/32 tests pass
- Demo runs without errors
- Binary size: 5.6M stripped (~200-300 bytes impact)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

1 files changed, 7 insertions, 7 deletions

diff --git a/src/test_demo.cc b/src/test_demo.cc
index 91c5427..4ec8d70 100644
--- a/src/test_demo.cc
+++ b/src/test_demo.cc
@@ -3,12 +3,12 @@
 
 #include "audio/audio.h"
 #include "audio/audio_engine.h"
-#include "util/check_return.h"
 #include "audio/synth.h"
 #include "generated/assets.h" // Note: uses main demo asset bundle
 #include "gpu/demo_effects.h"
 #include "gpu/gpu.h"
 #include "platform/platform.h"
+#include "util/check_return.h"
 #include <cmath>
 #include <cstdio>
 #include <cstdlib>
@@ -183,18 +183,18 @@ int main(int argc, char** argv) {
       }
     } else if (strcmp(argv[i], "--log-peaks") == 0) {
       CHECK_RETURN_BEGIN(i + 1 >= argc, 1)
-        print_usage(argv[0]);
-        ERROR_MSG("--log-peaks requires a filename argument\n");
-        return 1;
+      print_usage(argv[0]);
+      ERROR_MSG("--log-peaks requires a filename argument\n");
+      return 1;
       CHECK_RETURN_END
       log_peaks_file = argv[++i];
     } else if (strcmp(argv[i], "--log-peaks-fine") == 0) {
       log_peaks_fine = true;
     } else {
       CHECK_RETURN_BEGIN(true, 1)
-        print_usage(argv[0]);
-        ERROR_MSG("Unknown option '%s'\n", argv[i]);
-        return 1;
+      print_usage(argv[0]);
+      ERROR_MSG("Unknown option '%s'\n", argv[i]);
+      return 1;
       CHECK_RETURN_END
     }
   }