Dashboard: list the rules' quotas

A Quotas panel with each quota's allowance, use (or, per address, the
count and the busiest), a usage bar and the next reset. The usage bar
moves to widgets.js and the Rules page's usage dialog shares it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/rules.md

@@ -188,6 +188,10 @@ hc quotas                      # what each used, and the next reset
 hc rule reset-quota 31         # start again now
 ```
 
+In the web UI each quota's use is on its rule (with **Reset**), all of
+them together on the dashboard, and their history under **Traffic →
+Statistics**.
+
 | | |
 |---|---|
 | `per-source`, `per-destination` | each address its own allowance; without, one allowance for everything the rule matches |