feat(request-details): implement observability settings and enhance request detail tracking

- Added new observability settings in the dashboard for max records, batch size, flush interval, and max JSON size.
- Introduced `extractRequestConfig` function to capture full request configurations.
- Enhanced error handling by saving detailed request information on failures.
- Updated usage tracking to include new token metrics.
- Modified streaming functions to support detailed content and reasoning tracking.

src/app/api/usage/providers/route.js

@@ -0,0 +1,62 @@
+import { NextResponse } from "next/server";
+import { getRequestDetailsDb } from "@/lib/requestDetailsDb";
+import { getProviderNodes } from "@/lib/localDb";
+import { AI_PROVIDERS, getProviderByAlias } from "@/shared/constants/providers";
+
+/**
+ * GET /api/usage/providers
+ * Returns list of unique providers from request details
+ */
+export async function GET() {
+  try {
+    const db = await getRequestDetailsDb();
+
+    const stmt = db.prepare(`
+      SELECT DISTINCT provider
+      FROM request_details
+      WHERE provider IS NOT NULL AND provider != ''
+      ORDER BY provider ASC
+    `);
+
+    const rows = stmt.all();
+
+    // Fetch all provider nodes to get names for custom providers
+    const providerNodes = await getProviderNodes();
+    const nodeMap = {};
+    for (const node of providerNodes) {
+      nodeMap[node.id] = node.name;
+    }
+
+    const providers = rows.map(row => {
+      const providerId = row.provider;
+
+      // Try to find name from various sources
+      let name = providerId;
+
+      // 1. Check if it's a custom provider node
+      if (nodeMap[providerId]) {
+        name = nodeMap[providerId];
+      }
+      // 2. Check predefined providers
+      else {
+        const providerConfig = getProviderByAlias(providerId) || AI_PROVIDERS[providerId];
+        if (providerConfig?.name) {
+          name = providerConfig.name;
+        }
+      }
+
+      return {
+        id: providerId,
+        name
+      };
+    });
+
+    return NextResponse.json({ providers });
+  } catch (error) {
+    console.error("[API] Failed to get providers:", error);
+    return NextResponse.json(
+      { error: "Failed to fetch providers" },
+      { status: 500 }
+    );
+  }
+}