feat(character-animation): add local rigged character pipeline

New beta pipeline for reusable cartoon characters with SVG rigs, pose
libraries, action timelines, and Canvas/Remotion/HyperFrames rendering.

- pipeline_defs/character-animation.yaml: 11-stage manifest
- skills/pipelines/character-animation/: 11 stage director skills
- tools/character/: BaseTool implementations for char design, rigging,
  pose libraries, action timelines, previews, and QA
- schemas/artifacts/{character_design,rig_plan,pose_library,
  action_timeline,character_qa_report}.schema.json: canonical artifacts
- schemas/artifacts/scene_plan.schema.json: extended for character-led
  scenes
- .agents/skills/{canvas-procedural-animation,character-animation-qa,
  character-rigging,pose-library-design,svg-character-animation}/:
  Layer 3 vendor knowledge
- AGENT_GUIDE / PROJECT_CONTEXT / README / ARCHITECTURE / PROVIDERS:
  surface the new pipeline and its capability family
- tools/video/hyperframes_compose.py: SVG character rig support
- tests/contracts/test_character_animation_pipeline.py: contract tests

.agents/skills/canvas-procedural-animation/SKILL.md

@@ -0,0 +1,47 @@
+---
+name: canvas-procedural-animation
+description: Use p5.js/canvas for local procedural character effects: particles, weather, squash/stretch, walk cycles, and environmental motion.
+license: MIT
+---
+
+# Canvas Procedural Animation
+
+Use this skill when p5.js or Canvas is used for character-supporting motion:
+rain, snow, leaves, feathers, ambient particles, squash/stretch, or procedural
+walk cycles.
+
+## Proven Pattern
+
+p5.js runs setup once and redraws continuously through `draw()`. Keep animation
+state deterministic from time/frame values when rendering previews.
+
+```js
+function setup() {
+  createCanvas(1920, 1080);
+}
+
+function draw() {
+  const t = millis() / 1000;
+  clear();
+  drawCharacter(width / 2, height / 2 + sin(t * 8) * 8);
+}
+```
+
+## Use For
+
+- Particle/weather overlays.
+- Environmental motion.
+- Simple procedural bodies.
+- Effects that do not need individually authored SVG parts.
+
+## Avoid For
+
+- Complex facial acting where SVG/layered rig parts are easier to inspect.
+- Final renders that need exact frame determinism unless the runtime exposes
+  frame-index control.
+
+## Sources
+
+- p5.js `setup()` reference: https://p5js.org/reference/p5/setup/
+- p5.js `draw()` reference: https://p5js.org/reference/p5/draw/
+- p5.js animation examples: https://p5js.org/examples/