feat(deno): migrate sustainabot/bot-integration npm → Deno (standards#253) (#228)

## Summary

- Class A (pure-Deno port) migration for
`bots/sustainabot/bot-integration/`.
- Deletes redundant `package.json` stub (`private:true`, no deps,
scripts just mirror `deno.json`'s `affinescript compile`/`watch`/`clean`
tasks).
- `deno.json` is fully self-contained with full imports map
(`jsr:@std/{http,log,dotenv,crypto}`) — nothing else needed.
- Appends npm-avoidant `.gitignore` entries per standards#67
(package-lock.json, **/package-lock.json, bun.lockb, yarn.lock,
pnpm-lock.yaml, .npmrc).

## Refs

- standards#253 STEP 3 (smallest-first batch).
- Migration template:
`standards/docs/migrations/npm-to-deno-template/MIGRATION.md`.

## Test plan

- [x] Confirmed `package.json` is a pure stub (no runtime/build deps).
- [x] Confirmed `deno.json` carries all
build/watch/clean/smee/test/lint/fmt tasks.
- [x] `.gitignore` entries verified absent before append.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: hyperpolymath

.gitignore

@@ -137,3 +137,11 @@ deps/
 .cache/
 build/
 dist/
+
+# npm-avoidant (standards#67)
+package-lock.json
+**/package-lock.json
+bun.lockb
+yarn.lock
+pnpm-lock.yaml
+.npmrc