feat(webui): server-side SVG charts + reanimator-chart viewer

Metrics:
- Replace canvas JS charts with server-side SVG via go-analyze/charts
- Add ring buffers (120 samples) for CPU temp and power
- /api/metrics/chart/{name}.svg endpoint serves live SVG, polled every 2s

Dashboard:
- Replace custom renderViewerPage with viewer.RenderHTML() from reanimator/chart submodule
- Mount chart static assets at /chart/static/

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

audit/go.mod

@@ -1,3 +1,17 @@
 module bee/audit
 
 go 1.24.0
+
+replace reanimator/chart => ../internal/chart
+
+require (
+	github.com/go-analyze/charts v0.5.26
+	reanimator/chart v0.0.0-00010101000000-000000000000
+)
+
+require (
+	github.com/dustin/go-humanize v1.0.1 // indirect
+	github.com/go-analyze/bulk v0.1.3 // indirect
+	github.com/golang/freetype v0.0.0-20170609003504-e2365dfdc4a0 // indirect
+	golang.org/x/image v0.24.0 // indirect
+)