opencode prices and Go limits, settings out of .env

- Fetch prices for opencode (Zen and Go) incl. limits, image input, reasoning,
  long-context tiers and peak-hour/date factors; costs apply them per request
- Record the cost opencode reports per response; track Go allowance in 5h/7d/month
  windows against a provider plan limit (budget table, status overlay)
- Settings → Config file: move values of ${NAME} references into the config
- Examples, presets and forms keep keys in the config instead of .env

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

web/src/components/StatusLeds.tsx

@@ -1,9 +1,10 @@
 import { useCallback, useEffect, useRef, useState } from "react";
 import { get, post } from "../api";
-import { useT, type Key } from "../i18n";
+import { fmtPercent, useT, type Key } from "../i18n";
 import { navigate } from "../router";
 import { useStore } from "../store";
 import { Icon } from "./Icon";
+import type { Plan } from "./Budget";
 
 type Level = "ok" | "warn" | "err" | "off";
 
@@ -13,6 +14,7 @@ interface ProviderState {
   checked_at?: number;
   error?: string | null;
   models: number;
+  plan?: Plan | null;
 }
 interface McpEntry {
   state: "connected" | "connecting" | "failed";
@@ -38,7 +40,16 @@ function combine(levels: Level[]): Level {
   return "err";
 }
 
-const providerLevel = (p: ProviderState): Level => (p.state === "ok" ? "ok" : p.state === "unknown" ? "warn" : "err");
+/** The fullest window of a subscription plan (5 hours, week, month). */
+const fullest = (plan?: Plan | null) => plan?.windows.reduce((a, b) => (b.ratio > a.ratio ? b : a));
+
+const providerLevel = (p: ProviderState): Level => {
+  const health: Level = p.state === "ok" ? "ok" : p.state === "unknown" ? "warn" : "err";
+  const w = fullest(p.plan);
+  // A used-up plan blocks requests just like a rejected key.
+  const plan: Level = !w ? "ok" : w.ratio >= 1 ? "err" : w.ratio >= 0.8 ? "warn" : "ok";
+  return health === "err" || plan === "err" ? "err" : health === "warn" || plan === "warn" ? "warn" : "ok";
+};
 const mcpLevel = (m: McpEntry): Level => (m.state === "connected" ? "ok" : m.state === "connecting" ? "warn" : "err");
 
 function Led({ level, title }: { level: Level; title?: string }) {
@@ -164,7 +175,10 @@ export function StatusLeds() {
               <div key={name} className="status-row" title={p.error ?? undefined}>
                 <Led level={providerLevel(p)} />
                 <span className="grow mono">{name}</span>
-                <span className="hint">{providerText(p)}</span>
+                <span className="hint">
+                  {providerText(p)}
+                  {fullest(p.plan) && ` · ${t("status.plan", { pct: fmtPercent(fullest(p.plan)!.ratio), window: t(`budget.window.${fullest(p.plan)!.window}` as Key) })}`}
+                </span>
               </div>
             ))}
           </div>