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, 29 insertions, 8 deletions

diff --git a/tools/seq_compiler.cc b/tools/seq_compiler.cc
index 4a6b554..d89ab3d 100644
--- a/tools/seq_compiler.cc
+++ b/tools/seq_compiler.cc
@@ -38,7 +38,8 @@ std::string trim(const std::string& str) {
 }
 
 // Parse key=value parameters from extra_args string
-// Example: "color=1.0,0.0,0.0 decay=0.95" -> {{"color", "1.0,0.0,0.0"}, {"decay", "0.95"}}
+// Example: "color=1.0,0.0,0.0 decay=0.95" -> {{"color", "1.0,0.0,0.0"},
+// {"decay", "0.95"}}
 std::vector<std::pair<std::string, std::string>>
 parse_parameters(const std::string& args) {
   std::vector<std::pair<std::string, std::string>> params;
@@ -167,8 +168,8 @@ void analyze_effect_depth(const std::vector<SequenceEntry>& sequences,
   std::cout << "Sample rate: " << sample_rate << " Hz (every " << dt << "s)\n";
   std::cout << "\n";
 
-  std::cout << "Max concurrent effects: " << max_depth << " at t=" << max_depth_time
-            << "s\n";
+  std::cout << "Max concurrent effects: " << max_depth
+            << " at t=" << max_depth_time << "s\n";
   std::cout << "\n";
 
   // Print histogram
@@ -200,7 +201,8 @@ void analyze_effect_depth(const std::vector<SequenceEntry>& sequences,
   // Print bottleneck warnings
   if (max_depth > 5) {
     std::cout << "\n⚠ WARNING: Performance bottlenecks detected!\n";
-    std::cout << "Found " << peaks.size() << " time periods with >5 effects:\n\n";
+    std::cout << "Found " << peaks.size()
+              << " time periods with >5 effects:\n\n";
 
     int peak_count = 0;
     for (const auto& peak : peaks) {
@@ -850,7 +852,8 @@ int main(int argc, char* argv[]) {
       std::string extra_args = "";
       if (!rest_of_line.empty()) {
         params = parse_parameters(rest_of_line);
-        // Keep extra_args for backward compatibility (if no key=value pairs found)
+        // Keep extra_args for backward compatibility (if no key=value pairs
+        // found)
         if (params.empty()) {
           extra_args = ", " + rest_of_line;
         }
@@ -937,9 +940,27 @@ int main(int argc, char* argv[]) {
             }
           }
 
-          out_file << "      seq->add_effect(std::make_shared<" << eff.class_name
-                   << ">(ctx, p), " << eff.start << "f, " << eff.end << "f, "
-                   << eff.priority << ");\n";
+          out_file << "      seq->add_effect(std::make_shared<"
+                   << eff.class_name << ">(ctx, p), " << eff.start << "f, "
+                   << eff.end << "f, " << eff.priority << ");\n";
+          out_file << "    }\n";
+        } else if (!eff.params.empty() &&
+                   eff.class_name == "ChromaAberrationEffect") {
+          // Generate parameter struct initialization for ChromaAberrationEffect
+          out_file << "    {\n";
+          out_file << "      ChromaAberrationParams p;\n";
+
+          for (const auto& [key, value] : eff.params) {
+            if (key == "offset") {
+              out_file << "      p.offset_scale = " << value << "f;\n";
+            } else if (key == "angle") {
+              out_file << "      p.angle = " << value << "f;\n";
+            }
+          }
+
+          out_file << "      seq->add_effect(std::make_shared<"
+                   << eff.class_name << ">(ctx, p), " << eff.start << "f, "
+                   << eff.end << "f, " << eff.priority << ");\n";
           out_file << "    }\n";
         } else {
           // No parameters or unsupported effect - use default constructor