fix(uk-intake): drop data/countries.json change (governance lane only)

The previous force-push left the registry entry in this culture/*
branch's diff. The branch-scope contract forbids that:

  culture/<X>  ->  regions/<region>/<country>/** + safe metadata

data/countries.json is in GOVERNANCE_GLOB_PATTERNS (see
tests/branch_scope.py), not safe metadata, so culture/uk-intake
cannot touch it. The CI flagged this via "cultures - Branch scope
diff check" and "pr-gate - Diff within branch scope".

Registry intake for UK happens on the sibling
governance/registry-intake-united-kingdom branch (already exists,
PR pending). After that lands on main and the next sync brings it
down to culture/release, the UK content here connects to the
registry entry via the rebase.

This commit reverts data/countries.json on this branch to its
culture/release state -- no change from the file's authoritative
parent.

https://claude.ai/code/session_01PaUEPspVUzy36LUZ4t1yEU

Author: claude

data/countries.json

@@ -128,15 +128,6 @@
       "language": "de",
       "name_source": "BFS_CH_2023"
     },
-    {
-      "id": "united_kingdom",
-      "name": "United Kingdom",
-      "region": "europe",
-      "asset": "cultures-europe-united_kingdom.zip",
-      "anchor": { "type": "region", "iso": "GB" },
-      "language": "en",
-      "name_source": "ONS_GB_2022"
-    },
     {
       "id": "schleswig_holstein",
       "name": "Schleswig Holstein",