revert: upgrade marked package from ^15.0.7 to ^16.0.0

- Revert marked package version to ^16.0.0 for better compatibility
- Update pnpm-lock.yaml to reflect the version change
- Add changeset to document the dependency update
- All tests pass with the reverted version
- Build completes successfully

Author: shubhamparikh2704

.changeset/revert-marked-dependency.md

@@ -0,0 +1,9 @@
+---
+'mermaid': patch
+---
+
+chore: revert marked dependency from ^15.0.7 to ^16.0.0
+
+- Reverted marked package version to ^16.0.0 for better compatibility
+- This is a dependency update that maintains API compatibility
+- All tests pass with the updated version

packages/mermaid/package.json

@@ -82,7 +82,7 @@
     "katex": "^0.16.22",
     "khroma": "^2.1.0",
     "lodash-es": "^4.17.21",
-    "marked": "^15.0.7",
+    "marked": "^16.0.0",
     "roughjs": "^4.6.6",
     "stylis": "^4.3.6",
     "ts-dedent": "^2.2.0",