ci: count regex matches not content delta in version-sync assertion (#150)

The version-sync step asserted `new != s`, which fires when parent and
example versions already agree (the rewrite is an identity no-op, no
content change). Post-merge run on main hit this immediately because
the parent is at 6.1.0 and the example was already pinned to 6.1.0.

Use re.subn to count matches and assert count >= 1 — a no-op rewrite
when versions match is the expected steady state; a zero-match means
the pom layout drifted and CI should fail loud.

Author: saurabhjain1592

.github/workflows/integration.yml

@@ -141,18 +141,24 @@ jobs:
           echo "Parent SDK version: ${PARENT_VERSION}"
           # Replace the axonflow-sdk dependency version in examples/basic/pom.xml.
           # Anchored on the artifactId on the previous line to avoid touching
-          # other deps.
+          # other deps. Asserts the regex matched (count >= 1) so a layout
+          # drift fails CI loud; a no-op rewrite (versions already match)
+          # is fine.
           python3 - <<PY
           import re, pathlib
           p = pathlib.Path("examples/basic/pom.xml")
           s = p.read_text()
-          new = re.sub(
+          new, count = re.subn(
               r"(<artifactId>axonflow-sdk</artifactId>\s*<version>)[^<]+(</version>)",
               rf"\g<1>${PARENT_VERSION}\g<2>",
               s,
           )
-          assert new != s, "Failed to rewrite example pom version"
-          p.write_text(new)
+          assert count >= 1, "Regex did not match — examples/basic/pom.xml layout drifted"
+          if new != s:
+              p.write_text(new)
+              print(f"Rewrote example pom version to ${PARENT_VERSION}")
+          else:
+              print(f"Example pom already at parent version ${PARENT_VERSION} (no-op)")
           PY
           grep -A 1 "axonflow-sdk" examples/basic/pom.xml | head -4