fix(ci): add User-Agent header to crates.io API request

The crates.io API requires a User-Agent header for all requests.
Without it, curl was silently failing, causing the semver check
to be incorrectly skipped even though the crate is published.

Author: suchapalaver

.github/workflows/release.yml

@@ -42,7 +42,8 @@ jobs:
       - name: Check semver compatibility
         run: |
           # Skip semver check if this is the first release (crate not yet on crates.io)
-          if curl -sf "https://crates.io/api/v1/crates/semioscan" | grep -q '"name":"semioscan"'; then
+          # Note: crates.io API requires User-Agent header
+          if curl -sfA "semioscan-ci (https://github.com/semiotic-ai/semioscan)" "https://crates.io/api/v1/crates/semioscan" | grep -q '"name":"semioscan"'; then
             cargo semver-checks check-release
           else
             echo "Skipping semver check: semioscan not yet published to crates.io"