fix(geoblock): match country codes case-insensitively

[SashaMIT]

Description

Country blocks compared the configured code to MaxMind's ISO code with ==. MaxMind returns uppercase codes (CU). A list entry of cu did not match, so the request was allowed. Subdivision codes already ignore ASCII case. The country check now does too.

The visitor does not choose the block list. A lowercase entry in the operator's config fails open and serves traffic from a country the operator meant to block.

No existing issue.

How Has This Been Tested?

cargo test -p geoip --features middleware test_country_blocked

The new test configures cu against a resolver that returns CU and expects 401. Reverting the comparison makes that test return 200.

cargo +nightly-2026-02-11 fmt --all -- --check passed.
cargo +nightly-2026-02-11 clippy -p geoip --all-features --all-targets -- -D warnings passed.

Due Diligence

• Breaking change
• Requires a documentation update
• Requires a e2e/integration test update