feat: Update local agent documentation to reflect changes in user_id and session_id handling; add marketing strategy document; update skills-lock.json with new Remotion best practices; update website subproject commit.

.claude/skills/remotion-best-practices/rules/transitions.md

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+---
+name: transitions
+description: Scene transitions and overlays for Remotion using TransitionSeries.
+metadata:
+  tags: transitions, overlays, fade, slide, wipe, scenes
+---
+
+## TransitionSeries
+
+`<TransitionSeries>` arranges scenes and supports two ways to enhance the cut point between them:
+
+- **Transitions** (`<TransitionSeries.Transition>`) — crossfade, slide, wipe, etc. between two scenes. Shortens the timeline because both scenes play simultaneously during the transition.
+- **Overlays** (`<TransitionSeries.Overlay>`) — render an effect (e.g. a light leak) on top of the cut point without shortening the timeline.
+
+Children are absolutely positioned.
+
+## Prerequisites
+
+```bash
+npx remotion add @remotion/transitions
+```
+
+## Transition example
+
+```tsx
+import { TransitionSeries, linearTiming } from "@remotion/transitions";
+import { fade } from "@remotion/transitions/fade";
+
+<TransitionSeries>
+  <TransitionSeries.Sequence durationInFrames={60}>
+    <SceneA />
+  </TransitionSeries.Sequence>
+  <TransitionSeries.Transition
+    presentation={fade()}
+    timing={linearTiming({ durationInFrames: 15 })}
+  />
+  <TransitionSeries.Sequence durationInFrames={60}>
+    <SceneB />
+  </TransitionSeries.Sequence>
+</TransitionSeries>;
+```
+
+## Overlay example
+
+Any React component can be used as an overlay. For a ready-made effect, see the **light-leaks** rule.
+
+```tsx
+import { TransitionSeries } from "@remotion/transitions";
+import { LightLeak } from "@remotion/light-leaks";
+
+<TransitionSeries>
+  <TransitionSeries.Sequence durationInFrames={60}>
+    <SceneA />
+  </TransitionSeries.Sequence>
+  <TransitionSeries.Overlay durationInFrames={20}>
+    <LightLeak />
+  </TransitionSeries.Overlay>
+  <TransitionSeries.Sequence durationInFrames={60}>
+    <SceneB />
+  </TransitionSeries.Sequence>
+</TransitionSeries>;
+```
+
+## Mixing transitions and overlays
+
+Transitions and overlays can coexist in the same `<TransitionSeries>`, but an overlay cannot be adjacent to a transition or another overlay.
+
+```tsx
+import { TransitionSeries, linearTiming } from "@remotion/transitions";
+import { fade } from "@remotion/transitions/fade";
+import { LightLeak } from "@remotion/light-leaks";
+
+<TransitionSeries>
+  <TransitionSeries.Sequence durationInFrames={60}>
+    <SceneA />
+  </TransitionSeries.Sequence>
+  <TransitionSeries.Overlay durationInFrames={30}>
+    <LightLeak />
+  </TransitionSeries.Overlay>
+  <TransitionSeries.Sequence durationInFrames={60}>
+    <SceneB />
+  </TransitionSeries.Sequence>
+  <TransitionSeries.Transition
+    presentation={fade()}
+    timing={linearTiming({ durationInFrames: 15 })}
+  />
+  <TransitionSeries.Sequence durationInFrames={60}>
+    <SceneC />
+  </TransitionSeries.Sequence>
+</TransitionSeries>;
+```
+
+## Transition props
+
+`<TransitionSeries.Transition>` requires:
+
+- `presentation` — the visual effect (e.g. `fade()`, `slide()`, `wipe()`).
+- `timing` — controls speed and easing (e.g. `linearTiming()`, `springTiming()`).
+
+## Overlay props
+
+`<TransitionSeries.Overlay>` accepts:
+
+- `durationInFrames` — how long the overlay is visible (positive integer).
+- `offset?` — shifts the overlay relative to the cut point center. Positive = later, negative = earlier. Default: `0`.
+
+## Available transition types
+
+Import transitions from their respective modules:
+
+```tsx
+import { fade } from "@remotion/transitions/fade";
+import { slide } from "@remotion/transitions/slide";
+import { wipe } from "@remotion/transitions/wipe";
+import { flip } from "@remotion/transitions/flip";
+import { clockWipe } from "@remotion/transitions/clock-wipe";
+```
+
+## Slide transition with direction
+
+```tsx
+import { slide } from "@remotion/transitions/slide";
+
+<TransitionSeries.Transition
+  presentation={slide({ direction: "from-left" })}
+  timing={linearTiming({ durationInFrames: 20 })}
+/>;
+```
+
+Directions: `"from-left"`, `"from-right"`, `"from-top"`, `"from-bottom"`
+
+## Timing options
+
+```tsx
+import { linearTiming, springTiming } from "@remotion/transitions";
+
+// Linear timing - constant speed
+linearTiming({ durationInFrames: 20 });
+
+// Spring timing - organic motion
+springTiming({ config: { damping: 200 }, durationInFrames: 25 });
+```
+
+## Duration calculation
+
+Transitions overlap adjacent scenes, so the total composition length is **shorter** than the sum of all sequence durations. Overlays do **not** affect the total duration.
+
+For example, with two 60-frame sequences and a 15-frame transition:
+
+- Without transitions: `60 + 60 = 120` frames
+- With transition: `60 + 60 - 15 = 105` frames
+
+Adding an overlay between two other sequences does not change the total.
+
+### Getting the duration of a transition
+
+Use the `getDurationInFrames()` method on the timing object:
+
+```tsx
+import { linearTiming, springTiming } from "@remotion/transitions";
+
+const linearDuration = linearTiming({
+  durationInFrames: 20,
+}).getDurationInFrames({ fps: 30 });
+// Returns 20
+
+const springDuration = springTiming({
+  config: { damping: 200 },
+}).getDurationInFrames({ fps: 30 });
+// Returns calculated duration based on spring physics
+```
+
+For `springTiming` without an explicit `durationInFrames`, the duration depends on `fps` because it calculates when the spring animation settles.
+
+### Calculating total composition duration
+
+```tsx
+import { linearTiming } from "@remotion/transitions";
+
+const scene1Duration = 60;
+const scene2Duration = 60;
+const scene3Duration = 60;
+
+const timing1 = linearTiming({ durationInFrames: 15 });
+const timing2 = linearTiming({ durationInFrames: 20 });
+
+const transition1Duration = timing1.getDurationInFrames({ fps: 30 });
+const transition2Duration = timing2.getDurationInFrames({ fps: 30 });
+
+const totalDuration =
+  scene1Duration +
+  scene2Duration +
+  scene3Duration -
+  transition1Duration -
+  transition2Duration;
+// 60 + 60 + 60 - 15 - 20 = 145 frames
+```