Integrate .bazel_fix_commands.json with Bazelisk

bazel-watcher allows automatically running remediation scripts/commands in response to Bazel output invoked via bazel-watcher. It seems like this could be pretty useful functionality for a one-shot Bazel wrapper such as Bazelisk as well.

Start by examining how Bazelisk invokes Bazel and how bazel-watcher discovers and runs .bazel_fix_commands.json remediation commands. Compare that behavior with Bazelisk's current launcher flow and document the integration boundaries and expected command semantics. Done should include an agreed design and coverage for the supported remediation behavior.

Written by the indexing model from the issue text.