chore: migrate release-please to manifest config

Switch .github/release-please.yml to manifest mode and add release-please-config.json plus .release-please-manifest.json for source-controlled release configuration/state.

Configure changelog sections so chore/docs/refactor are releasable while style/test/build/ci remain hidden.

Author: taeold

.github/release-please.yml

@@ -1,2 +1,6 @@
-releaseType: node
 handleGHRelease: true
+manifest: true
+branches:
+  - branch: main
+    releaseType: node
+    handleGHRelease: true

.release-please-manifest.json

@@ -0,0 +1,3 @@
+{
+  ".": "5.0.0"
+}

release-please-config.json

@@ -0,0 +1,62 @@
+{
+  "$schema": "https://raw.githubusercontent.com/googleapis/release-please/main/schemas/config.json",
+  "release-type": "node",
+  "packages": {
+    ".": {
+      "changelog-sections": [
+        {
+          "type": "feat",
+          "section": "Features"
+        },
+        {
+          "type": "fix",
+          "section": "Bug Fixes"
+        },
+        {
+          "type": "perf",
+          "section": "Performance Improvements"
+        },
+        {
+          "type": "revert",
+          "section": "Reverts"
+        },
+        {
+          "type": "deps",
+          "section": "Dependencies"
+        },
+        {
+          "type": "chore",
+          "section": "Miscellaneous Chores"
+        },
+        {
+          "type": "docs",
+          "section": "Documentation"
+        },
+        {
+          "type": "refactor",
+          "section": "Code Refactoring"
+        },
+        {
+          "type": "style",
+          "section": "Styles",
+          "hidden": true
+        },
+        {
+          "type": "test",
+          "section": "Tests",
+          "hidden": true
+        },
+        {
+          "type": "build",
+          "section": "Build System",
+          "hidden": true
+        },
+        {
+          "type": "ci",
+          "section": "Continuous Integration",
+          "hidden": true
+        }
+      ]
+    }
+  }
+}