feat(scripts): make-demo-gif.sh — produce optimized README hero GIF (Closes #7)

[hacka0wi]

Summary

Adds scripts/make-demo-gif.sh — turns a .mov screen recording into a README-ready optimized GIF.

Pipeline

1. ffmpeg trim + scale + fps + drop audio → intermediate mp4
2. gifski (perceptual quantizer, preferred) or ffmpeg palettegen+paletteuse (fallback) → final GIF

The two-stage approach means input codec/container doesn't matter — works for QuickTime .mov, OBS .mp4, ScreenStudio .mov, etc.

Defaults

Tuned for UI demos:

DURATION	15 s
WIDTH	900 px
FPS	15
TARGET_MAX_MB	10

All overridable as env vars. Script warns (doesn't fail) when output exceeds the soft limit and suggests three knobs to turn.

Usage

scripts/make-demo-gif.sh ~/Desktop/runloop-demo.mov
# → docs/screenshots/flow-editor.gif

# narrower for smaller size
WIDTH=720 scripts/make-demo-gif.sh ~/Desktop/runloop-demo.mov

Closes

Closes #7

Follow-up (separate PR, after first GIF is recorded)

Update README hero to <picture> block:

<picture>
  <source srcset="docs/screenshots/flow-editor.gif" type="image/gif">
  <img src="docs/screenshots/flow-editor.png" alt="...">
</picture>

Test plan

• Bash syntax (bash -n) clean
• Usage error path triggers on missing arg
• Detects missing ffmpeg, prints install hint
• CI green
• Manual record + run produces GIF (next: record actual demo)