feat(deno): migrate broad-spectrum npm → Deno (standards#253) (#154)

## Summary

Class B (npm-wrapper via Deno) migration of `broad-spectrum/` sub-tree.

- Deletes `broad-spectrum/package.json` (stub: rescript + @rescript/core
+ gentype devDeps; scripts wrapping rescript)
- Updates `broad-spectrum/deno.json` to add wrapped
`build`/`clean`/`watch` tasks: `deno run -A --node-modules-dir=auto
npm:rescript <args>`
- Appends npm-avoidant lock-file patterns to root `.gitignore`

Triage note: deno.json already exists and had Deno-native
`audit`/`test`/`dev`/`fmt`/`lint` tasks. The `build`/`clean`/`watch`
lifecycle previously living in package.json is now wrapped via Deno's
`npm:` specifier so functionality survives the delete. No `gentype` task
was bare-referenced anywhere.

Scope: only `broad-spectrum/` + root `.gitignore`. No lock files were
present to remove.

Refs: standards#253 STEP 3 (smallest-first batch).

## Test plan

- [ ] CI green on default checks
- [ ] `deno task -c broad-spectrum/deno.json build` resolves rescript
via npm: specifier (post-merge spot-check optional)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: hyperpolymath

.gitignore

@@ -98,3 +98,11 @@ node_modules/
 .cache/
 build/
 dist/
+
+# npm-avoidant (standards#67)
+package-lock.json
+**/package-lock.json
+bun.lockb
+yarn.lock
+pnpm-lock.yaml
+.npmrc

broad-spectrum/deno.json

@@ -1,5 +1,8 @@
 {
   "tasks": {
+    "build": "deno run -A --node-modules-dir=auto npm:rescript build",
+    "clean": "deno run -A --node-modules-dir=auto npm:rescript clean",
+    "watch": "deno run -A --node-modules-dir=auto npm:rescript build -w",
     "audit": "deno run --allow-net --allow-read --allow-env src/Main.js",
     "test": "deno run --allow-net --allow-read --allow-env tests/UrlParser_test.js",
     "dev": "deno run --watch --allow-net --allow-read --allow-env src/Main.js",