Build optimization: pre-built PM3 binaries, ARM64 CI, base image caching

Replace PM3 compile-from-source in pi-gen with pre-built tarball extraction
(saves 43-58 min). Merge stagePM3 into stageDangerousPi as 02-pm3-install
substage, renumber all subsequent substages. Switch CI PM3 build to native
ARM64 runner (ubuntu-24.04-arm64) eliminating QEMU overhead. Add weekly
base-image workflow for pre-baking stages 0-2. Support PM3_TARBALL,
BASE_IMAGE, and APT_PROXY env vars in build-image.sh.

Also includes prior Phase 5 work: theme system, design system integration,
component update system, OS updates, CI build pipeline, and test results.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/frontend/package-lock.json

@@ -8,6 +8,7 @@
       "name": "dangerous-pi-frontend",
       "version": "0.1.0",
       "dependencies": {
+        "@dangerousthings/web": "file:../../../dt-design-system/packages/web",
         "@remix-run/node": "^2.14.0",
         "@remix-run/react": "^2.14.0",
         "@remix-run/serve": "^2.14.0",
@@ -26,6 +27,22 @@
         "node": ">=18.0.0"
       }
     },
+    "../../../dt-design-system/packages/web": {
+      "name": "@dangerousthings/web",
+      "version": "0.2.0",
+      "license": "MIT",
+      "dependencies": {
+        "@dangerousthings/tokens": "*"
+      }
+    },
+    "../../../dt-web-theme": {
+      "version": "0.1.0",
+      "extraneous": true,
+      "license": "MIT"
+    },
+    "../../dt-web-theme": {
+      "extraneous": true
+    },
     "node_modules/@babel/code-frame": {
       "version": "7.27.1",
       "resolved": "https://registry.npmjs.org/@babel/code-frame/-/code-frame-7.27.1.tgz",
@@ -515,6 +532,10 @@
         "node": ">=6.9.0"
       }
     },
+    "node_modules/@dangerousthings/web": {
+      "resolved": "../../../dt-design-system/packages/web",
+      "link": true
+    },
     "node_modules/@emotion/hash": {
       "version": "0.9.2",
       "resolved": "https://registry.npmjs.org/@emotion/hash/-/hash-0.9.2.tgz",