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/pose-library-design/SKILL.md

@@ -0,0 +1,58 @@
+---
+name: pose-library-design
+description: Design reusable 2D character pose libraries, action cycles, and expression states for data-driven animation.
+license: MIT
+---
+
+# Pose Library Design
+
+Use this skill when producing `pose_library` artifacts.
+
+## Pose Categories
+
+- Neutral: idle, breathe, listening.
+- Attention: look_up, look_down, look_left, look_right.
+- Emotion: happy, sad, surprised, worried, determined.
+- Action: reach, point, hold, jump, flap, walk_contact, walk_passing.
+- Mouth: closed, small_o, wide_open, smile, frown, phoneme-ish shapes.
+
+## Acting Pattern
+
+Use timed pose sequences:
+
+```text
+anticipation -> action -> hold -> settle
+```
+
+Do not continuously animate every part. Holds make the acting readable.
+
+## Pose Data Pattern
+
+```json
+{
+  "pose": "surprised",
+  "parts": {
+    "head": { "rotation": -6, "y": -4 },
+    "pupil_left": { "x": 4, "y": -6 },
+    "mouth": "small_o"
+  },
+  "hold_frames": 18,
+  "transition": "back.out"
+}
+```
+
+## Quality Checklist
+
+- Required emotions have poses.
+- Required actions have poses or cycles.
+- Reused cycles have contact and passing poses.
+- Poses name only changed parts; defaults come from the rig.
+
+## Sources
+
+- GSAP timeline sequencing for readable multi-step poses:
+  https://gsap.com/docs/v3/GSAP/Timeline/
+- Remotion interpolation for frame-based transitions:
+  https://www.remotion.dev/docs/interpolate
+- Remotion spring for natural motion:
+  https://www.remotion.dev/docs/spring