skills: adopt GSAP Layer 3 + Layer 2 animation-runtime routing

Mirror the official GSAP AI skills (greensock/gsap-skills, MIT) into
.agents/skills/ and add the Layer 2 wiring that makes them discoverable
from a fresh context.

GSAP covers animation needs that Remotion primitives strain at:
per-character text reveals (SplitText), SVG shape morphs (MorphSVG),
curved camera paths (MotionPath), stroke-reveal line drawing (DrawSVG),
layout-to-layout flight (Flip), and custom bezier easings (CustomEase).
Also becomes mandatory day-1 knowledge if we wire in HyperFrames later
(HF uses GSAP timelines as its native animation runtime).

Layer 3 adds (.agents/skills/):
- gsap-core, gsap-timeline, gsap-plugins, gsap-utils
- gsap-react, gsap-performance
- gsap-scrolltrigger, gsap-frameworks (situational)
- gsap/README.md — OpenMontage-specific framing and Remotion-safe usage

Layer 2 wiring (the discovery triggers):
- skills/meta/animation-runtime-selector.md — NEW routing meta-skill.
  Decision matrix covering Remotion primitives, GSAP plugins, framer-
  motion, Lottie, Manim, D3, TerminalScene. Enforces the "keep it
  simple" bias: reach for GSAP only when the plugin genuinely earns
  its bundle weight.
- skills/pipelines/explainer/asset-director.md — references GSAP for
  kinetic typography, multi-step choreography, SVG line draws.
- skills/pipelines/animation/asset-director.md — references GSAP for
  logo morphs, motion paths, FLIP transitions, custom easings.
- skills/pipelines/cinematic/asset-director.md — references GSAP for
  cinematic camera moves, per-char title reveals, prestige easings.
- AGENT_GUIDE.md — adds a categorized Layer 3 skills table so a fresh-
  context agent can find the right skill by what they're trying to do,
  plus a pointer to animation-runtime-selector.md for routing.

Determinism: every GSAP use inside Remotion must drive timeline progress
from useCurrentFrame(), never requestAnimationFrame. Three Remotion-safe
patterns are documented in both the gsap/README and the selector skill.

Attribution: https://github.com/greensock/gsap-skills (MIT).

skills/pipelines/cinematic/asset-director.md

@@ -4,6 +4,23 @@
 
 This stage prepares the usable media for the final cinematic edit: source selects, title-card assets, optional support inserts, music, ambience, and subtitle assets when needed.
 
+## Animation authoring for cinematic titles and overlays
+
+Before authoring title cards, name plates, or SVG overlays, read **`skills/meta/animation-runtime-selector.md`** for runtime routing. Cinematic pieces lean on a handful of high-craft motion patterns:
+
+| Cinematic need | Recommended approach |
+|---|---|
+| Hero title with subtle reveal | Remotion `HeroTitle` component (existing) |
+| Logo build / cinematic sting on SVG | GSAP DrawSVG + MotionPath — read `.agents/skills/gsap-plugins/SKILL.md` |
+| Curved camera move across a wide still or overlay | GSAP MotionPath — read `.agents/skills/gsap-plugins/SKILL.md` |
+| Per-character title reveal (prestige / trailer style) | GSAP SplitText — read `.agents/skills/gsap-plugins/SKILL.md` |
+| Cinematic easings (Unreal-style, stuttering, weighted) | GSAP CustomEase / EasePack — read `.agents/skills/gsap-plugins/SKILL.md` |
+| Name plate lower-third with elastic settle | Remotion `spring()` is usually enough; GSAP CustomEase if you need stutter |
+| Film grain / particle overlay | Remotion `ParticleOverlay` (existing) |
+| Color grade / LUT | `tools/enhancement/color_grade.py` (not an animation concern) |
+
+**Cinematic is where GSAP earns its weight most often** — the genre rewards crafted easings and precise curved motion that primitive `interpolate()` struggles to express cleanly. Don't over-use it either: for a fade-in title, Remotion `spring()` still beats a whole GSAP dependency.
+
 ## Prerequisites
 
 | Layer | Resource | Purpose |