feat: v0.1.4 — device intelligence dashboard

Add tabbed dashboard at /dashboard/ with three D3.js visualizations:
- Vendor treemap (devices grouped by type and vendor)
- SSID social graph (force-directed, shared probed SSIDs as edges)
- Fingerprint clusters (packed circles by device behavior)

Intelligence API endpoints at /api/v1/intelligence/ with param
validation. Dashboard built on htmx + Pico CSS dark theme + D3 v7,
all vendored locally (make vendor). 13 new tests (59 total).

Makefile

@@ -1,4 +1,4 @@
-.PHONY: help build run dev stop logs test migrate clean install start restart status oui cleanup
+.PHONY: help build run dev stop logs test migrate clean install start restart status oui cleanup vendor
 
 APP_NAME := esp32-web
 PORT := 5500
@@ -115,6 +115,12 @@ container-stop:
 container-logs:
 	podman logs -f $(APP_NAME)
 
+vendor:
+	mkdir -p static/css/vendor static/js/vendor static/js/viz
+	curl -sLo static/css/vendor/pico.min.css https://cdn.jsdelivr.net/npm/@picocss/pico@2/css/pico.min.css
+	curl -sLo static/js/vendor/htmx.min.js https://unpkg.com/htmx.org@2.0.4/dist/htmx.min.js
+	curl -sLo static/js/vendor/d3.min.js https://cdn.jsdelivr.net/npm/d3@7/dist/d3.min.js
+
 clean:
 	rm -rf __pycache__ .pytest_cache .ruff_cache
 	find . -type d -name __pycache__ -exec rm -rf {} +