chore(deps): sweep 2026-09-08 (#84)

## Summary

Routine dependency sweep, dev-only. No runtime dependency changed and no
release is needed.

- `@types/node` 26.4.1 to 26.5.0.
- Drop the `nanoid` override. With the override removed and the lock
re-resolved, every locked copy of nanoid still lands on 3.3.18, the
fixed release for GHSA-2v37-7h3g-55p8, so the floor was inert. Verified
by removing every override, reinstalling, and diffing resolved versions.
- Keep the `esbuild` override: the same drill showed tsup resolving
esbuild 0.27.7 without it.
- `packageManager` to bun 1.4.2, the current release.

Held on purpose: eslint 9 and TypeScript 6 (org-wide holds),
`typescript-eslint` 8.70.0 (inside the 24h release soak at sweep time;
dependabot will propose it). GitHub Actions pins audited and current
(checkout, cache, setup-bun, setup-node all on their latest majors). OSV
scan over the lock: no issues.

Worked with Varun (varunwadhwa).

## Type of change

- [ ] Bug fix (no breaking change)
- [ ] New feature (no breaking change)
- [ ] Breaking change (existing callers must update)
- [x] Docs, tests, or internal maintenance only

## Public API

none

## Test plan

Ran locally on the branch: `bun run lint`, `bun run typecheck`, `bun run
knip`, `bun run test` (166 passed, 9 skipped), `bun run build`, all exit
0. `osv-scanner scan --lockfile bun.lock`: 456 packages, no issues.

## Checklist

- [x] Tests cover the new behavior, and the suite passes locally
- [x] Lint, format, and type checks pass
- [x] Docs and README examples updated if the public surface changed
- [x] No secrets, credentials, or personal data in the diff or the tests

Co-authored-by: Claude Fable 5.1 <noreply@anthropic.com>

Author: vvillait88

bun.lock

@@ -54,7 +54,7 @@
   },
   "devDependencies": {
     "@eslint/js": "^9.39.5",
-    "@types/node": "^26.4.1",
+    "@types/node": "^26.5.0",
     "@vitest/coverage-v8": "^5.0.0",
     "dotenv": "^17.4.2",
     "eslint": "^9.39.5",
@@ -67,9 +67,8 @@
     "typescript-eslint": "^8.69.0",
     "vitest": "^5.0.0"
   },
-  "packageManager": "bun@1.4.0",
+  "packageManager": "bun@1.4.2",
   "overrides": {
-    "esbuild": "^0.28.1",
-    "nanoid": "^3.3.17"
+    "esbuild": "^0.28.1"
   }
 }