add README to _tools/ documenting project scripts

Author: cderv

_tools/README.md

@@ -0,0 +1,29 @@
+# Project Scripts (`_tools/`)
+
+Utility scripts for the quarto-web project. Run with `quarto run` (TypeScript, R, Python, or Lua).
+
+## Scripts
+
+| Script | Language | Description |
+|--------|----------|-------------|
+| `publish-date.ts` | TypeScript | Set a blog post date to today and rename its directory to match |
+| `algolia-add-custom-attribute.ts` | TypeScript | Post-render hook: adds custom attributes to Algolia search index |
+| `reference.ts` | TypeScript | Generate reference documentation |
+| `reference-cli-generate-md.R` | R | Generate CLI reference markdown |
+| `gallery-screenshot.R` | R | Capture gallery screenshots |
+| `sort-gallery.R` | R | Sort gallery entries |
+| `release-notes.R` | R | Generate release notes content |
+| `snapshot-typst.ts` | TypeScript | Capture Typst document snapshots as PNG |
+
+## Usage
+
+```bash
+# Run any script
+quarto run _tools/<script> [args]
+
+# Examples
+quarto run _tools/publish-date.ts docs/blog/posts/2026-04-10-my-post
+quarto run _tools/snapshot-typst.ts source.qmd dest.png
+```
+
+TypeScript scripts use the Deno runtime bundled with Quarto (no external install needed). R scripts require R/Rscript on PATH.