freehire-search: us is a country, not a region (#630)

* freehire-search: us is a country, not a region

The docs and --help listed us as a --region value. In freehire's location
dictionary us is a country code and the region is north_america, so
--region us matched 168 'software engineer' postings against 100008 for
--country us. List the real region vocabulary and send single-country
searches to --country.

* freehire-search: add uk to the region list; fix the README row

* changelog: place the #630 entry under [Unreleased]

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Mads Lorentzen <madslorentzen_17@hotmail.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

.agents/skills/freehire-search/url-reference.md

@@ -68,7 +68,7 @@ Query parameters used by the skill:
 | `limit` | `--limit` / `-n` | Page size. Default 25 in the CLI. |
 | `offset` | (derived) | `offset = (page - 1) * limit`. |
 | `posted_within_days` | `--jobage` | Restrict to postings from the last N days. |
-| `regions` | `--region` | Repeatable; OR within the facet. Values like `global`, `eu`, `us`, `apac`, `latam`, `cis`. |
+| `regions` | `--region` | Repeatable; OR within the facet. Values: `global`, `eu`, `uk`, `north_america`, `latam`, `apac`, `mena`, `africa`, `cis`. `us` is a country (`countries`), not a region. |
 | `countries` | `--country` | Repeatable; ISO-3166 alpha-2 (lowercased). |
 | `cities` | `--city` | Repeatable; display-name city. |
 | `seniority` | `--seniority` | Repeatable; `junior`, `middle`, `senior`, `staff`, … |