feat: Implement Sequence and Effect system for demo choreography

Refactors the rendering pipeline into a modular Sequence/Effect system. 'MainSequence' manages the final frame rendering and a list of 'Sequence' layers. 'Sequence' manages a timeline of 'Effect' objects (start/end/priority). Concrete effects (Heptagon, Particles) are moved to 'demo_effects.cc'. Updates main loop to pass beat and aspect ratio.

1 files changed, 5 insertions, 1 deletions

diff --git a/PROJECT_CONTEXT.md b/PROJECT_CONTEXT.md
index ddde463..24b1517 100644
--- a/PROJECT_CONTEXT.md
+++ b/PROJECT_CONTEXT.md
@@ -35,8 +35,12 @@ Incoming tasks in no particular order:
 - [x] 7. compile wgpu-native in optimized mode (not unoptimized)
 - [x] 8. add a #define STRIP_ALL to remove all unnecessary code for the final build (for instance, command-line args parsing, or unnecessary options, constant parameters to function calls, etc.)
 - [x] 9. work on the compact in-line and off-line asset system (@ASSET_SYSTEM.md)
-- [x] 10. optimize spectool to remove trailing zeroes from a spec file before saving it
+- 10. optimize spectool to remove trailing zeroes from a spec file before saving it
 - [x] 11. implement a general [time / timer / beat] system in the demo, for effects timing
+- 12. Implement 'Sequence' and 'Effect' system:
+    - `Effect` interface: `start()`, `draw(time, beat, intensity)`, `end()`.
+    - `Sequence` manager: Handles a list of potentially overlapping effects.
+    - `time` is relative to sequence start. `beat` is a [0..1] pulse. `intensity` is signal strength (e.g. music level).
 
 ## Session Decisions and Current State