diff --git a/.github/workflows/scheduled-security-scan.yml b/.github/workflows/scheduled-security-scan.yml
index 8ecb5185..6b19cf25 100644
--- a/.github/workflows/scheduled-security-scan.yml
+++ b/.github/workflows/scheduled-security-scan.yml
@@ -90,13 +90,13 @@ jobs:
         with:
           persist-credentials: false
       - name: Initialize CodeQL
-        uses: github/codeql-action/init@99df26d4f13ea111d4ec1a7dddef6063f76b97e9 # v4.37.0
+        uses: github/codeql-action/init@f205ea1c3313d32999d8d6a48b4f6530d4437b38 # v4.37.4
         with:
           languages: ${{ matrix.language }}
           build-mode: ${{ matrix.build-mode }}
       - name: Perform CodeQL Analysis
         continue-on-error: true
-        uses: github/codeql-action/analyze@99df26d4f13ea111d4ec1a7dddef6063f76b97e9 # v4.37.0
+        uses: github/codeql-action/analyze@f205ea1c3313d32999d8d6a48b4f6530d4437b38 # v4.37.4
         with:
           category: "/language:${{ matrix.language }}-scheduled"
 
diff --git a/scripts/ci/pr_review_merge_scheduler.py b/scripts/ci/pr_review_merge_scheduler.py
index 75e18c86..dd0c0a43 100644
--- a/scripts/ci/pr_review_merge_scheduler.py
+++ b/scripts/ci/pr_review_merge_scheduler.py
@@ -12,6 +12,7 @@
 import subprocess
 import sys
 import time
+import unicodedata
 from collections.abc import Sequence
 from dataclasses import dataclass
 from datetime import datetime, timezone
@@ -126,7 +127,7 @@
 RUNNING_CHECK_STATES = {"PENDING", "EXPECTED", "QUEUED", "IN_PROGRESS", "WAITING", "REQUESTED"}
 FAILED_CHECK_CONCLUSIONS = {"FAILURE", "ERROR", "CANCELLED", "TIMED_OUT", "STARTUP_FAILURE"}
 ACTION_REQUIRED_CONCLUSIONS = {"ACTION_REQUIRED"}
-GIT_REF_RE = re.compile(r"^(?!-)[A-Za-z0-9._/-]+$")
+GIT_REF_ASCII_SAFE_CHARS = frozenset("._/-")
 GIT_SHA_RE = re.compile(r"^[0-9a-fA-F]{40}$")
 GITHUB_REPOSITORY_RE = re.compile(r"^[A-Za-z0-9_.-]+/[A-Za-z0-9_.-]+$")
 REVIEW_BODY_HEAD_SHA_RE = re.compile(r"Head SHA:\s*`([0-9a-fA-F]{40})`")
@@ -529,12 +530,24 @@ def split_repo(repo: str) -> tuple[str, str]:
 
 
 def validate_git_ref(ref: str) -> str:
-    """Return a conservative Git ref name for gh workflow dispatch fields."""
+    """Return a conservative Unicode-capable Git ref for structured argv/JSON fields."""
+    has_unsafe_character = isinstance(ref, str) and any(
+        (
+            character.isascii()
+            and not (character.isalnum() or character in GIT_REF_ASCII_SAFE_CHARS)
+        )
+        or (
+            not character.isascii()
+            and unicodedata.category(character)[0] in {"C", "Z"}
+        )
+        for character in ref
+    )
     if (
         not isinstance(ref, str)
         or not ref
-        or not GIT_REF_RE.fullmatch(ref)
+        or has_unsafe_character
         or ref == "HEAD"
+        or ref.startswith("-")
         or ref.startswith("/")
         or ref.endswith(("/", "."))
         or "@{" in ref
@@ -542,7 +555,10 @@ def validate_git_ref(ref: str) -> str:
         or "//" in ref
     ):
         raise ValueError(f"invalid git ref: {ref!r}")
-    if any(part == "." or part.startswith(".") for part in ref.split("/")):
+    if any(
+        part == "." or part.startswith(".") or part.endswith(".lock")
+        for part in ref.split("/")
+    ):
         raise ValueError(f"invalid git ref: {ref!r}")
     return ref
 
diff --git a/tests/test_pr_review_merge_scheduler.py b/tests/test_pr_review_merge_scheduler.py
index 3e421e90..f7aa640d 100644
--- a/tests/test_pr_review_merge_scheduler.py
+++ b/tests/test_pr_review_merge_scheduler.py
@@ -162,7 +162,12 @@ def test_run_split_repo_and_graphql(monkeypatch):
     with pytest.raises(ValueError):
         sched.split_repo("/repo")
 
-    assert sched.validate_git_ref("feature/safe.branch-1") == "feature/safe.branch-1"
+    for valid_ref in (
+        "feature/safe.branch-1",
+        "🎨-palette-ux-improvement-13325911538352561627",
+        "기능/달력-개선",
+    ):
+        assert sched.validate_git_ref(valid_ref) == valid_ref
     for bad_ref in (
         "",
         "-bad",
@@ -172,8 +177,11 @@ def test_run_split_repo_and_graphql(monkeypatch):
         "feature/./main",
         "feature//main",
         "feature/main.",
+        "feature/main.lock",
         "feature/@{upstream}",
         "feat;echo pwned",
+        "feature/\u00a0hidden",
+        "feature/\u200bhidden",
     ):
         with pytest.raises(ValueError):
             sched.validate_git_ref(bad_ref)
@@ -1891,6 +1899,7 @@ def test_missing_evidence_dispatch_uses_central_required_workflow_repository(mon
     calls = []
     head_sha = "a" * 40
     base_sha = "b" * 40
+    head_ref = "🎨-palette-ux-improvement-13325911538352561627"
 
     def fake_run_with_env(args, *, stdin=None, env=None):
         calls.append((args, stdin, None if env is None else env.get("GH_TOKEN")))
@@ -1905,7 +1914,12 @@ def fake_run_with_env(args, *, stdin=None, env=None):
     monkeypatch.setenv("SCHEDULER_REQUIRED_WORKFLOW_REPOSITORY", "ContextualWisdomLab/.github")
     monkeypatch.setenv("SCHEDULER_REQUIRED_WORKFLOW_REF", "main")
 
-    pr = make_pr(baseRefName="develop", baseRefOid=base_sha, headRefOid=head_sha)
+    pr = make_pr(
+        baseRefName="develop",
+        baseRefOid=base_sha,
+        headRefName=head_ref,
+        headRefOid=head_sha,
+    )
     sched.dispatch_strix_evidence("owner/repo", "Strix Security Scan", pr, dry_run=False)
     sched.dispatch_opencode_review("owner/repo", "OpenCode Review", pr, dry_run=False)
 
@@ -1950,7 +1964,7 @@ def fake_run_with_env(args, *, stdin=None, env=None):
             "pr_number": 1,
             "pr_base_ref": "develop",
             "pr_base_sha": base_sha,
-            "pr_head_ref": "feature",
+            "pr_head_ref": head_ref,
             "pr_head_sha": head_sha,
         },
     }