feat(factory): add native Droid plugin packaging (#120)

* feat(factory): add native Droid plugin packaging

* test(factory): guard documented install contract

* fix(factory): enforce install command order

.factory-plugin/marketplace.json

@@ -0,0 +1,9 @@
+{
+  "name": "diagram-design",
+  "plugins": [
+    {
+      "name": "diagram-design",
+      "source": "./"
+    }
+  ]
+}

.factory-plugin/plugin.json

@@ -0,0 +1,25 @@
+{
+  "name": "diagram-design",
+  "description": "Create branded architecture, IT current-state, flowchart, sequence, state machine, ER/data model, timeline, swimlane, quadrant, radar/spider, loop/flywheel, nested, tree, org chart, layer stack, Venn, pyramid/funnel, treemap, bar, line, Gantt and scatter charts, high-level, process, medallion, data flow, DP integration, DP security matrix, sankey, fishbone, Wardley map, kanban, user journey, deployment, dependency graph, UML class, story map, or database schema diagrams as standalone HTML/SVG/PNG. Redraw .drawio/.drawio.png/.drawio.svg or Mermaid .mmd sources at a chosen size/detail; onboard brand tokens from a website; add semantic patterns, callouts, accessible motion, or sketchy/hand-drawn styling.",
+  "version": "2.5.14",
+  "author": {
+    "name": "Cathryn Lavery",
+    "url": "https://github.com/cathrynlavery"
+  },
+  "homepage": "https://github.com/cathrynlavery/diagram-design",
+  "repository": "https://github.com/cathrynlavery/diagram-design",
+  "license": "MIT",
+  "keywords": [
+    "diagrams",
+    "svg",
+    "architecture",
+    "flowchart",
+    "visualization",
+    "editorial",
+    "drawio",
+    "mermaid",
+    "import",
+    "animation",
+    "semantic-patterns"
+  ]
+}