Enforce block statements with Biome's useBlockStatements #666

Problem

Control-flow bodies are written both ways across the codebase:

if (error instanceof ReleaseKitError) return true;

if (error instanceof ReleaseKitError) {
  return true;
}

The block form should be the only one. Nothing enforces it today: biome.jsonc turns style/useBlockStatements off explicitly, and eslint.config.js has no curly rule.

Size

With the rule set to error, Biome 2.5.6 reports 703 violations in 134 files:

Every one is auto-fixable. Biome marks the fix unsafe by default, so it needs --unsafe:

biome lint --write --unsafe --only=style/useBlockStatements .

Proposal

1. Enable the rule and mark its fix safe, so the pre-commit biome check --write (lint-staged) adds the braces automatically instead of only reporting them:

   "style": {
     "useBlockStatements": { "level": "error", "fix": "safe" }
   }

   Checked: with this config, biome check --write without --unsafe rewrites if (x) return true; into the block form.

2. Apply the fix across the repo in one mechanical commit, and add that commit to .git-blame-ignore-revs (the file doesn't exist yet) so git blame skips it.

3. Run pnpm lint, pnpm typecheck and pnpm test on the result. The fix only adds braces, but scripts/ and test files are in scope too.

Sequencing

The sweep touches most source files, so it will conflict with any open PR that edits them (currently #616, #617, #618 and #619). Either land it once those merge, or land it first and have each open branch run the same fix command before merging main: both sides then carry identical braces, so only real changes conflict.