Add Dependabot config and simplify deploy workflow

Introduces .github/dependabot.yml to automate dependency updates for npm and GitHub Actions. Streamlines the deploy job in depoly.yml by removing setup, install, lint, type-check, and test steps, focusing only on code checkout and deployment via Wrangler.

.github/dependabot.yml

@@ -0,0 +1,44 @@
+version: 2
+updates:
+  # Maintain npm dependencies
+  - package-ecosystem: "npm"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+      time: "09:00"
+    open-pull-requests-limit: 10
+    groups:
+      npm_and_yarn:
+        patterns:
+          - "*"
+    commit-message:
+      prefix: "chore"
+      prefix-development: "chore"
+      include: "scope"
+    labels:
+      - "dependencies"
+      - "npm"
+    reviewers:
+      - "xixu-me"
+    assignees:
+      - "xixu-me"
+
+  # Maintain GitHub Actions workflows
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "weekly"
+      day: "monday"
+      time: "09:00"
+    open-pull-requests-limit: 5
+    commit-message:
+      prefix: "ci"
+      include: "scope"
+    labels:
+      - "dependencies"
+      - "github-actions"
+    reviewers:
+      - "xixu-me"
+    assignees:
+      - "xixu-me"