README: the I-beam analysis demo, driven by an agent over MCP

The GIF plays inline and links the MP4; both are generated by tools/demo-video and attributed.
The asset check now also covers .mp4 files.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NmAttHhUZTokgPeEJia8sm

ATTRIBUTION.md

@@ -14,6 +14,7 @@ is committed and listed here with its exports.
 
 | File | Author | Source | Licence |
 |---|---|---|---|
+| docs/media/ibeam-analysis.mp4, docs/media/ibeam-analysis.gif | ModelCraft contributors | Original: the ModelCraft window captured during an MCP session, generated by `tools/demo-video/make.py` | MIT OR Apache-2.0 |
 | crates/decks/tests/golden/nastran/*.bdf | ModelCraft contributors | Written by our Nastran writer from our own test models (crates/decks/tests/nastran.rs) | MIT OR Apache-2.0 |
 | assets/icons/assembly.instance.svg, assets/icons/assembly.instance.vectorcraft | ModelCraft contributors | Original toolbar icon drawn with VectorCraft from `assets/icons/src/assembly.instance.json` (`cargo xtask icons`) | MIT OR Apache-2.0 |
 | assets/icons/deck.read.svg, assets/icons/deck.read.vectorcraft | ModelCraft contributors | Original toolbar icon drawn with VectorCraft from `assets/icons/src/deck.read.json` (`cargo xtask icons`) | MIT OR Apache-2.0 |

README.md

@@ -9,6 +9,13 @@ drive the same commands.
 geometry boundary (SolidCraft's kernel and tessellator) are in place; meshing is next. See
 [ROADMAP.md](ROADMAP.md).
 
+![An AI agent analyses an I-beam cantilever over MCP: open, hex mesh, steel, clamp and tip load, solve, von Mises contours and the deformed shape](docs/media/ibeam-analysis.gif)
+
+An AI agent drives the app over [MCP](docs/mcp.md): it opens an I-beam, hex meshes it, defines
+the material, the clamp and a 1000 N tip load, solves, and shows the von Mises stress and the
+deformed shape (tip deflection 0.176 mm; beam theory with shear 0.177 mm).
+[MP4](docs/media/ibeam-analysis.mp4) · regenerated by [tools/demo-video](tools/demo-video/README.md).
+
 ## Build
 
 ```sh

xtask/src/assets.rs

@@ -16,6 +16,7 @@ const ASSET_EXT: &[&str] = &[
     "woff",
     "woff2",
     "gif",
+    "mp4",
     "bmp",
     "webp",
     "wav",