List NLRB cases

Per-case NLRB enforcement records for an employer.

Each row is one National Labor Relations Board case carrying the case_number, type (case_type -- 'C-' for unfair labor practice filings, 'R-' for representation elections), status, filing region, and the filed / closed dates. Together with the employer-profile aggregates (nlrb_cases, nlrb_ulp_cases, nlrb_representation_cases, nlrb_last_case_date) this gives the full picture of an employer's NLRB footprint -- the aggregates show the headline numbers and this endpoint backs them with the underlying case roster.

Lookup: NLRB filings carry name + city + state but no zip5, so the join key is (name_normalized, state) -- resolved through the employer's own profile row. An employer's (name_normalized, state) pair is fetched from employer_profile, then the case detail is pulled from nlrb_case_detail on that pair. Most-recent case first.

Metered: one lookup per call, same as the other detail endpoints.