chore: add CI path filters, update README and images

- ci.yml: skip lint/test/docker on docs-only and markdown-only pushes
- deploy-docs.yml: only rebuild GitHub Pages when apps/docs/** changes
- README.md: updated key features and content
- images: updated dashboard screenshots, removed stale images

.github/workflows/ci.yml

@@ -3,8 +3,20 @@ name: CI
 on:
   push:
     branches: [main]
+    paths-ignore:
+      - "README.md"
+      - "CONTRIBUTING.md"
+      - "images/**"
+      - "apps/docs/**"
+      - "docs/**"
   pull_request:
     branches: [main]
+    paths-ignore:
+      - "README.md"
+      - "CONTRIBUTING.md"
+      - "images/**"
+      - "apps/docs/**"
+      - "docs/**"
 
 concurrency:
   group: ${{ github.workflow }}-${{ github.ref }}