build: token-monitor v0.1.0 — modular LLM API quota visibility

Implements modular provider probing with two distinct header schemas:
- Teams direct (unified schema): 5h/7d utilization floats, status, reset countdown
- Shelley proxy (classic schema): token/request counts + Exedev-Gateway-Cost (USD/call)
- api-ateam: reports no billing data (confirmed non-existent by recon)

Key: uses claude-haiku-4-5-20251001 for minimal probe calls (1 token).
Rate-limit headers present on ALL responses (200 and 429).

113/113 tests passing.

Built from Face recon (trentuna/a-team#91) — live header capture confirmed
unified schema with utilization floats replaces old per-count schema.

providers/anthropic-api.js

@@ -0,0 +1,75 @@
+/**
+ * anthropic-api.js — api-ateam (pay-per-use, api03 keys)
+ *
+ * Anthropic's REST API does not expose billing or quota data via any endpoint
+ * (confirmed by recon, issue trentuna/a-team#91). This module reports that
+ * billing data is unavailable — always. Key validity could be confirmed with
+ * a real HTTP call, but for monitoring purposes the static result is authoritative.
+ */
+
+import { getSeverity } from '../report.js';
+
+/**
+ * Return the static api-ateam status object.
+ * Synchronous — no HTTP call needed because no billing API exists.
+ * @returns {Object}
+ */
+export function getApiAteamStatus() {
+  return {
+    type: 'api-direct',
+    status: 'no_billing_data',
+    message: 'Anthropic API does not expose billing/quota via REST. Key validity not checked.',
+    severity: getSeverity({ type: 'api-direct' }),
+  };
+}
+
+/**
+ * Probe the api-ateam provider.
+ * Makes a minimal call to confirm key validity, but always reports no billing data.
+ * @param {string} providerName
+ * @param {string} baseUrl
+ * @param {string} apiKey
+ * @returns {Promise<Object>}
+ */
+export async function probeApiProvider(providerName, baseUrl, apiKey) {
+  try {
+    const response = await fetch(`${baseUrl}/v1/messages`, {
+      method: 'POST',
+      headers: {
+        'x-api-key': apiKey,
+        'anthropic-version': '2023-06-01',
+        'content-type': 'application/json',
+      },
+      body: JSON.stringify({
+        model: 'claude-haiku-4-5-20251001',
+        max_tokens: 1,
+        messages: [{ role: 'user', content: 'Hi' }],
+      }),
+    });
+
+    if (response.status === 401) {
+      return {
+        type: 'api-direct',
+        status: 'invalid_key',
+        message: 'Invalid API key (401)',
+        severity: 'unknown',
+      };
+    }
+
+    // No billing endpoint exists — always report no_billing_data
+    return {
+      type: 'api-direct',
+      status: 'no_billing_data',
+      message: 'Anthropic API does not expose billing/quota via REST. Key appears valid.',
+      http_status: response.status,
+      severity: 'unknown',
+    };
+  } catch (err) {
+    return {
+      type: 'api-direct',
+      status: 'error',
+      message: err.message,
+      severity: 'unknown',
+    };
+  }
+}