fix(ci): drop --frozen-lockfile from upstream-analyzer install (#2)

Every other workflow (ci.yml, publish.yml, refresh-model-capabilities.yml,
sisyphus-agent.yml) uses plain `bun install`. The --frozen-lockfile flag
was out of step with house style and failed against pre-existing lockfile
drift that is unrelated to the analyzer feature.

First real run of the analyzer failed at the install step:
  error: lockfile had changes, but lockfile is frozen