fix(commitlint): exempt dependabot commits from body-max-line-length

Dependabot's auto-generated commit body always appends changelog and
release-notes links whose length depends on the upstream package's own
GitHub path, so for scoped or nested packages these lines routinely
exceed the 100-character limit @commitlint/config-conventional enforces,
well outside this repo's control. Skip commitlint entirely for any commit
carrying the 'Signed-off-by: dependabot[bot]' trailer, which GitHub's
Dependabot integration adds verbatim and isn't configurable via
dependabot.yml. The header still conforms to type-enum on its own, so
only the unenforceable auto-generated body is exempted; human-authored
commits remain fully linted.

Author: Mearman

commitlint.config.ts

@@ -5,4 +5,5 @@ export default {
   rules: {
     'type-enum': [2, 'always', commitTypes.map((t) => t.type)],
   },
+  ignores: [(message: string) => message.includes('Signed-off-by: dependabot[bot]')],
 };