Update demo GIF with cleaner CLI examples

Show preflight commands directly without Docker build noise:
- Two passing checks (cmd version, env exists)
- Two failing checks (version constraint, pattern mismatch)

Author: vertti

README.md

@@ -7,7 +7,7 @@
 
 Stop copying brittle shell scripts and installing a variety of tools for container validation. Preflight is a small, dependency-free binary that handles service readiness, health checks, environment validation, file verification, and more.
 
-![demo](demo/demo.gif?v=2)
+![demo](demo/cli-demo.gif)
 
 ```dockerfile
 COPY --from=ghcr.io/vertti/preflight:latest /preflight /usr/local/bin/preflight

demo/cli-demo.gif

@@ -1,23 +1,23 @@
-Output demo.gif
+Output cli-demo.gif
 Set Shell bash
 Set FontSize 16
-Set Width 900
-Set Height 550
+Set Width 800
+Set Height 400
 Set Theme "Catppuccin Mocha"
 Set Padding 20
 
-Type "# Show what we're building"
+Type "preflight cmd node --min 18.0"
 Enter
-Sleep 500ms
+Sleep 2s
 
-Type "cat demo/Dockerfile"
+Type "preflight env HOME"
 Enter
-Sleep 4s
+Sleep 2s
 
-Type "# Run the build"
+Type "preflight cmd node --min 99.0"
 Enter
-Sleep 500ms
+Sleep 2s
 
-Type "docker build --progress=plain -f demo/Dockerfile ."
+Type "preflight env HOME --match '^/nonexistent'"
 Enter
-Sleep 10s
+Sleep 5s