fix(pr): allow merge-commit landings

scripts/pr

@@ -72,6 +72,7 @@ Usage:
   scripts/pr prepare-run <PR>
   scripts/pr merge-verify <PR>
   scripts/pr merge-run <PR>
+    OPENCLAW_PR_MERGE_METHOD=merge preserves the PR commit series.
 USAGE
 }
 

scripts/pr-lib/merge.sh

@@ -233,8 +233,26 @@ merge_run() {
     return 0
   }
 
+  local merge_method="${OPENCLAW_PR_MERGE_METHOD:-squash}"
+  local merge_flag
+  local merge_label
+  case "$merge_method" in
+    squash)
+      merge_flag="--squash"
+      merge_label="squash"
+      ;;
+    merge)
+      merge_flag="--merge"
+      merge_label="merge commit"
+      ;;
+    *)
+      echo "Invalid OPENCLAW_PR_MERGE_METHOD: $merge_method (expected squash or merge)."
+      exit 2
+      ;;
+  esac
+
   if ! gh pr merge "$pr" \
-    --squash \
+    "$merge_flag" \
     --match-head-commit "$PREP_HEAD_SHA" \
     >.local/merge-output.log 2>&1
   then
@@ -299,7 +317,7 @@ merge_run() {
   for attempt in 1 2 3; do
     if comment_output=$(
       {
-        echo "Merged via squash."
+        echo "Merged via $merge_label."
         echo
         echo "- Prepared head SHA: [$PREP_HEAD_SHA]($prep_sha_url)"
         echo "- Landed commit: [$landed_sha]($landed_sha_url)"

test/scripts/pr-wrappers.test.ts

@@ -35,13 +35,14 @@ describe("scripts/pr wrappers", () => {
     expect(script).toContain('exec "$base" merge-run "$pr"');
   });
 
-  it("uses the repository-approved squash landing method", () => {
+  it("defaults to squash and allows an explicit merge commit", () => {
     const script = readScript("scripts/pr-lib/merge.sh");
 
+    expect(script).toContain("OPENCLAW_PR_MERGE_METHOD:-squash");
     expect(script).toContain("--squash");
+    expect(script).toContain("--merge");
     expect(script).not.toContain("--rebase");
-    expect(script).toContain("Merged via squash.");
-    expect(script).not.toContain("Merged via rebase.");
+    expect(script).toContain('echo "Merged via $merge_label."');
   });
 
   it("keeps prepare wrapper modes delegated to the main PR helper", () => {