feat: lift 5-account cap on HTTP/2

app/api/auth/session/route.ts

@@ -13,6 +13,7 @@ import { configManager } from '@/lib/admin/config-manager';
 import { isPublicHttpUrl } from '@/lib/security/url-guard';
 import { recordLogin } from '@/lib/telemetry/login-tracker';
 import { parseJmapServers, resolveTrustedJmapUrl } from '@/lib/admin/jmap-servers';
+import { MAX_ACCOUNT_SLOTS } from '@/lib/account-utils';
 
 const COOKIE_OPTIONS = {
   ...getCookieOptions(),
@@ -23,7 +24,7 @@ function getSlot(request: NextRequest): number {
   const raw = request.nextUrl.searchParams.get('slot');
   if (raw === null) return 0;
   const slot = parseInt(raw, 10);
-  if (isNaN(slot) || slot < 0 || slot > 4) return 0;
+  if (isNaN(slot) || slot < 0 || slot >= MAX_ACCOUNT_SLOTS) return 0;
   return slot;
 }
 
@@ -70,7 +71,7 @@ export async function POST(request: NextRequest) {
       return NextResponse.json({ error: 'JMAP server not configured' }, { status: 500 });
     }
 
-    const slot = typeof bodySlot === 'number' && bodySlot >= 0 && bodySlot <= 4 ? bodySlot : getSlot(request);
+    const slot = typeof bodySlot === 'number' && bodySlot >= 0 && bodySlot < MAX_ACCOUNT_SLOTS ? bodySlot : getSlot(request);
     const cookieName = sessionCookieName(slot);
     const authHeader = `Basic ${Buffer.from(`${username}:${password}`).toString('base64')}`;
     const normalizedServerUrl = await verifyJmapAuth(upstreamUrl, authHeader, { trusted: upstreamTrusted });
@@ -185,8 +186,8 @@ export async function DELETE(request: NextRequest) {
     const all = request.nextUrl.searchParams.get('all') === 'true';
 
     if (all) {
-      // Delete all session cookies (slots 0-4)
-      for (let i = 0; i <= 4; i++) {
+      // Delete all session cookies across every slot.
+      for (let i = 0; i < MAX_ACCOUNT_SLOTS; i++) {
         cookieStore.delete(sessionCookieName(i));
         clearStalwartAuthContextInStore(cookieStore, i);
       }

app/api/auth/stalwart-context/route.ts

@@ -6,9 +6,10 @@ import { configManager } from '@/lib/admin/config-manager';
 import { isPublicHttpUrl } from '@/lib/security/url-guard';
 import { recordLogin } from '@/lib/telemetry/login-tracker';
 import { parseJmapServers, resolveTrustedJmapUrl } from '@/lib/admin/jmap-servers';
+import { MAX_ACCOUNT_SLOTS } from '@/lib/account-utils';
 
 function getSlot(request: NextRequest, bodySlot: unknown): number {
-  if (typeof bodySlot === 'number' && bodySlot >= 0 && bodySlot <= 4) {
+  if (typeof bodySlot === 'number' && bodySlot >= 0 && bodySlot < MAX_ACCOUNT_SLOTS) {
     return bodySlot;
   }
 
@@ -16,7 +17,7 @@ function getSlot(request: NextRequest, bodySlot: unknown): number {
   if (raw === null) return 0;
 
   const slot = parseInt(raw, 10);
-  return Number.isNaN(slot) || slot < 0 || slot > 4 ? 0 : slot;
+  return Number.isNaN(slot) || slot < 0 || slot >= MAX_ACCOUNT_SLOTS ? 0 : slot;
 }
 
 export async function POST(request: NextRequest) {

app/api/auth/token/route.ts

@@ -4,12 +4,13 @@ import { logger } from '@/lib/logger';
 import { refreshTokenCookieName, refreshTokenServerCookieName } from '@/lib/oauth/tokens';
 import { exchangeCodeForTokens, buildOAuthParams, getMetadata, getTokenEndpoint } from '@/lib/oauth/token-exchange';
 import { getCookieOptions } from '@/lib/oauth/cookie-config';
+import { MAX_ACCOUNT_SLOTS } from '@/lib/account-utils';
 
 function getSlot(request: NextRequest): number {
   const raw = request.nextUrl.searchParams.get('slot');
   if (raw === null) return 0;
   const slot = parseInt(raw, 10);
-  if (isNaN(slot) || slot < 0 || slot > 4) return 0;
+  if (isNaN(slot) || slot < 0 || slot >= MAX_ACCOUNT_SLOTS) return 0;
   return slot;
 }
 
@@ -21,7 +22,7 @@ export async function POST(request: NextRequest) {
       return NextResponse.json({ error: 'Missing required parameters' }, { status: 400 });
     }
 
-    const slot = typeof bodySlot === 'number' && bodySlot >= 0 && bodySlot <= 4 ? bodySlot : getSlot(request);
+    const slot = typeof bodySlot === 'number' && bodySlot >= 0 && bodySlot < MAX_ACCOUNT_SLOTS ? bodySlot : getSlot(request);
     const serverId = typeof bodyServerId === 'string' && bodyServerId ? bodyServerId : null;
 
     const tokens = await exchangeCodeForTokens(code, code_verifier, redirect_uri, serverId);
@@ -112,9 +113,9 @@ export async function DELETE(request: NextRequest) {
     const all = request.nextUrl.searchParams.get('all') === 'true';
 
     if (all) {
-      // Revoke and delete all refresh token cookies (slots 0-4)
+      // Revoke and delete all refresh token cookies across every slot.
       const cookieStore = await cookies();
-      for (let i = 0; i <= 4; i++) {
+      for (let i = 0; i < MAX_ACCOUNT_SLOTS; i++) {
         const name = refreshTokenCookieName(i);
         const serverCookieName = refreshTokenServerCookieName(i);
         const token = cookieStore.get(name)?.value;

app/api/auth/totp-token-exchange/route.ts

@@ -9,6 +9,7 @@ import { configManager } from '@/lib/admin/config-manager';
 import { isPublicHttpUrl } from '@/lib/security/url-guard';
 import { recordLogin } from '@/lib/telemetry/login-tracker';
 import { parseJmapServers, findServerByUrl, findServerById } from '@/lib/admin/jmap-servers';
+import { MAX_ACCOUNT_SLOTS } from '@/lib/account-utils';
 
 /**
  * Exchange basic auth credentials (with TOTP appended) for OAuth tokens.
@@ -85,7 +86,7 @@ export async function POST(request: NextRequest) {
       return NextResponse.json({ error: 'Missing required parameters' }, { status: 400 });
     }
 
-    const slot = typeof bodySlot === 'number' && bodySlot >= 0 && bodySlot <= 4 ? bodySlot : 0;
+    const slot = typeof bodySlot === 'number' && bodySlot >= 0 && bodySlot < MAX_ACCOUNT_SLOTS ? bodySlot : 0;
     const requestedServerId = typeof bodyServerId === 'string' && bodyServerId ? bodyServerId : null;
 
     // Pin the upstream URL to a configured JMAP server. The list of allowed