feat(config): lower MCP timeouts and raise JSON body limit

Reduce the default external-MCP silence timeout from 5 min to 1 min and the
overall call timeout from 15 min to 2 min. Update related tests and comments.
Increase Fastify's JSON body limit to 25 MiB (configurable via
HTTP_JSON_BODY_LIMIT) to accommodate large AI‑chat payloads.

BREAKING CHANGE: shorter MCP timeouts may abort long‑running tool calls that
previously succeeded with the older defaults.

apps/server/src/core/ai-chat/external-mcp/mcp-call-timeout.spec.ts

@@ -181,25 +181,25 @@ describe('mcp timeout env helpers', () => {
     else process.env.AI_MCP_CALL_TIMEOUT_MS = ORIG_CALL;
   });
 
-  it('mcpStreamTimeoutMs defaults to 5 min and honors a positive override', () => {
+  it('mcpStreamTimeoutMs defaults to 1 min and honors a positive override', () => {
     delete process.env.AI_MCP_STREAM_TIMEOUT_MS;
-    expect(mcpStreamTimeoutMs()).toBe(300_000);
-    process.env.AI_MCP_STREAM_TIMEOUT_MS = '60000';
     expect(mcpStreamTimeoutMs()).toBe(60_000);
+    process.env.AI_MCP_STREAM_TIMEOUT_MS = '90000';
+    expect(mcpStreamTimeoutMs()).toBe(90_000);
     for (const bad of ['0', '-1', 'x', '']) {
       process.env.AI_MCP_STREAM_TIMEOUT_MS = bad;
-      expect(mcpStreamTimeoutMs()).toBe(300_000);
+      expect(mcpStreamTimeoutMs()).toBe(60_000);
     }
   });
 
-  it('mcpCallTimeoutMs defaults to 15 min and honors a positive override', () => {
+  it('mcpCallTimeoutMs defaults to 2 min and honors a positive override', () => {
     delete process.env.AI_MCP_CALL_TIMEOUT_MS;
-    expect(mcpCallTimeoutMs()).toBe(900_000);
-    process.env.AI_MCP_CALL_TIMEOUT_MS = '120000';
     expect(mcpCallTimeoutMs()).toBe(120_000);
+    process.env.AI_MCP_CALL_TIMEOUT_MS = '180000';
+    expect(mcpCallTimeoutMs()).toBe(180_000);
     for (const bad of ['0', '-1', 'x', '']) {
       process.env.AI_MCP_CALL_TIMEOUT_MS = bad;
-      expect(mcpCallTimeoutMs()).toBe(900_000);
+      expect(mcpCallTimeoutMs()).toBe(120_000);
     }
   });
 });

apps/server/src/core/ai-chat/external-mcp/mcp-clients.service.ts

@@ -523,12 +523,12 @@ export function validateResolvedAddresses(addrs: readonly LookupAddress[]): {
  */
 function buildPinnedDispatcher(): Agent {
   // External-MCP traffic uses a DEDICATED, shorter silence timeout
-  // (`AI_MCP_STREAM_TIMEOUT_MS`, default 5 min) — deliberately tighter than the
+  // (`AI_MCP_STREAM_TIMEOUT_MS`, default 1 min) — deliberately tighter than the
   // chat provider's 15-min `streamTimeoutMs()` — so a byte-silent/hung MCP
-  // upstream is broken in ~5 min instead of 15. We keep the keep-alive options
+  // upstream is broken in ~1 min instead of 15. We keep the keep-alive options
   // from `streamingDispatcherOptions()` but OVERRIDE headers/body timeouts.
   // Accepted trade-off: a legitimately long but byte-silent single tool call,
-  // and an SSE transport idling >5 min BETWEEN tool calls, are also cut here; the
+  // and an SSE transport idling >1 min BETWEEN tool calls, are also cut here; the
   // per-call total cap (wrapToolsWithCallTimeout, `AI_MCP_CALL_TIMEOUT_MS`) is the
   // complementary guard for chatty-but-stuck calls that keep the socket warm yet
   // never return.