feat(opencode-zen): add OpenCode Zen (PAYG) provider with free-tier fingerprint, alias ocz

Multi-endpoint provider on https://opencode.ai/zen/v1 (openai / claude /
openai-responses transports mirroring opencode-go) with 71 models across
paid + free tiers. Free-tier fingerprint: opencode/1.18.x UA spoof,
ses_-session header, built-in tool quartet, forced stream. Usage endpoint
/zen/v1/usage wired into the dashboard.

open-sse/services/usage.js

@@ -15,6 +15,7 @@ import { getGrokCliUsage } from "./usage/grok-cli.js";
 import { getKimiUsage } from "./usage/kimi.js";
 import { getDeepseekUsage } from "./usage/deepseek.js";
 import { getOpenCodeGoUsage } from "./usage/opencode-go.js";
+import { getOpenCodeZenUsage } from "./usage/opencode-zen.js";
 import { getGroqUsage } from "./usage/groq.js";
 import { getZedUsage } from "./usage/zed.js";
 import { getXiaomiMimoUsage } from "./usage/xiaomi-mimo.js";
@@ -59,6 +60,7 @@ const USAGE_HANDLERS = {
   "grok-cli": (c) => getGrokCliUsage(c.accessToken, c.providerSpecificData, c.proxyOptions),
   kimi: (c) => getKimiUsage(c.accessToken, c.apiKey, c.proxyOptions, c.providerSpecificData),
   "opencode-go": (c) => getOpenCodeGoUsage(c.apiKey, c.proxyOptions),
+  "opencode-zen": (c) => getOpenCodeZenUsage(c.apiKey, c.proxyOptions),
   deepseek: (c) => getDeepseekUsage(c.apiKey, c.proxyOptions),
   groq: (c) => getGroqUsage(c.apiKey, c.proxyOptions),
   zed: (c) => getZedUsage(c.accessToken, c.providerSpecificData, c.proxyOptions),

open-sse/services/usage/opencode-zen.js

@@ -0,0 +1,107 @@
+/**
+ * OpenCode Zen usage — GET https://opencode.ai/zen/v1/usage
+ * Auth: Bearer <apiKey>
+ */
+
+import { proxyAwareFetch } from "../../utils/proxyFetch.js";
+import { parseResetTime, toFiniteNumber, U } from "./shared.js";
+
+const USAGE_URL = U("opencode-zen").url;
+const QUOTA_NAMES = {
+  rolling: "Rolling",
+  weekly: "Weekly",
+  monthly: "Monthly",
+};
+
+function parsePercent(value) {
+  if (typeof value === "number" && Number.isFinite(value)) return value;
+  if (typeof value === "string" && value.trim()) {
+    const parsed = Number(value);
+    if (Number.isFinite(parsed)) return parsed;
+  }
+  return null;
+}
+
+export async function getOpenCodeZenUsage(apiKey = null, proxyOptions = null) {
+  if (!apiKey || typeof apiKey !== "string" || !apiKey.trim()) {
+    return {
+      message: "OpenCode Zen API key not available. Add a key to view usage.",
+    };
+  }
+
+  try {
+    const response = await proxyAwareFetch(
+      USAGE_URL,
+      {
+        method: "GET",
+        headers: {
+          Authorization: `Bearer ${apiKey.trim()}`,
+          Accept: "application/json",
+        },
+      },
+      proxyOptions,
+    );
+
+    if (response.status === 401) {
+      return {
+        plan: "OpenCode Zen",
+        message: "OpenCode Zen authentication failed. Check the API key.",
+      };
+    }
+
+    if (response.status === 403) {
+      const error = await response.json().catch(() => null);
+      const subscriptionRequired = error?.error?.type === "EntitlementError";
+      return {
+        plan: "OpenCode Zen",
+        message: subscriptionRequired
+          ? "OpenCode Zen billing required for this API key."
+          : "OpenCode Zen access forbidden for this API key.",
+      };
+    }
+
+    if (!response.ok) {
+      return {
+        plan: "OpenCode Zen",
+        message: `OpenCode Zen usage API error (${response.status}).`,
+      };
+    }
+
+    const data = await response.json().catch(() => null);
+    if (!data?.usage || typeof data.usage !== "object") {
+      return {
+        plan: "OpenCode Zen",
+        message: "OpenCode Zen usage response did not contain quota data.",
+      };
+    }
+
+    const quotas = {};
+    for (const [period, name] of Object.entries(QUOTA_NAMES)) {
+      const quota = data.usage[period];
+      if (!quota || typeof quota !== "object") continue;
+      const percent = parsePercent(quota.percent);
+      if (percent === null) continue;
+      const used = Math.max(0, Math.min(100, toFiniteNumber(percent, 0)));
+      quotas[name] = {
+        used,
+        total: 100,
+        remaining: 100 - used,
+        remainingPercentage: 100 - used,
+        resetAt: parseResetTime(quota.resetsAt),
+        unlimited: false,
+      };
+    }
+
+
+    if (Object.keys(quotas).length === 0) {
+      return {
+        plan: "OpenCode Zen",
+        message: "OpenCode Zen usage response did not contain valid quota data.",
+      };
+    }
+
+    return { plan: "OpenCode Zen", quotas };
+  } catch (error) {
+    return { message: `OpenCode Zen error: ${error.message}` };
+  }
+}