The user wants me to create a single-page web app using p5.min.js that's already in the current directory. I need to build an L-system fractal tree that grows procedurally and sways in the wind. Let me first check that p5.min.js exists, then write the index.html file.

Good, the file exists. Now let me create the index.html with a full L-system fractal tree that grows and sways.

Let me verify the file is there and looks good.

Done! Here's what I built:

**`/tmp/ws/index.html`** — A self-contained L-system fractal tree that:

1. **Procedural L-System** — Uses the classic "X" axiom with rules `X → F+[[X]-X]-F[-FX]+X` and `F → FF`, generating 7 iterations for a rich branching structure (thousands of segments).

2. **Growth Animation** — Segments reveal from bottom to top in a smooth wave, giving the impression of the tree sprouting upward over ~4 seconds.

3. **Wind Swaying** — Multiple layered sine waves create organic wind turbulence. Each branch sways proportionally to its depth — upper branches flutter more than sturdy lower trunks. The sway is perpendicular to each branch direction.

4. **Visual Polish**:
   - Dark night sky gradient background
   - Twinkling stars
   - Ground with grass tufts that also sway
   - Color transitions from warm brown bark at the trunk → green leaf tones at branch tips
   - Floating cherry-blossom particles drifting in the breeze
   - Depth-based stroke thickness (thick trunk tapering to hair-fine twigs)
   - Fully responsive to window resize

No external dependencies beyond the bundled `p5.min.js` — zero network requests.