fix: gate paired runtime on dual registrations

src/db.test.ts

@@ -17,6 +17,7 @@ import {
   getAllRegisteredGroups,
   getDueTasks,
   getEffectiveRoomMode,
+  getEffectiveRuntimeRoomMode,
   getExplicitRoomMode,
   getLatestMessageSeqAtOrBefore,
   getLatestPairedTaskForChat,
@@ -824,6 +825,7 @@ describe('paired room registration', () => {
 
     expect(getExplicitRoomMode('dc:legacy-paired')).toBeUndefined();
     expect(getEffectiveRoomMode('dc:legacy-paired')).toBe('tribunal');
+    expect(getEffectiveRuntimeRoomMode('dc:legacy-paired')).toBe('tribunal');
     expect(isPairedRoomJid('dc:legacy-paired')).toBe(true);
   });
 
@@ -847,10 +849,11 @@ describe('paired room registration', () => {
 
     expect(getExplicitRoomMode('dc:explicit-single')).toBe('single');
     expect(getEffectiveRoomMode('dc:explicit-single')).toBe('single');
+    expect(getEffectiveRuntimeRoomMode('dc:explicit-single')).toBe('single');
     expect(isPairedRoomJid('dc:explicit-single')).toBe(false);
   });
 
-  it('lets explicit tribunal override solo fallback and clears back to inferred mode', () => {
+  it('keeps explicit tribunal configured but not runnable without dual registration', () => {
     setRegisteredGroup('dc:explicit-tribunal', {
       name: 'Explicit Tribunal Claude',
       folder: 'explicit-tribunal-claude',
@@ -865,12 +868,14 @@ describe('paired room registration', () => {
 
     expect(getExplicitRoomMode('dc:explicit-tribunal')).toBe('tribunal');
     expect(getEffectiveRoomMode('dc:explicit-tribunal')).toBe('tribunal');
-    expect(isPairedRoomJid('dc:explicit-tribunal')).toBe(true);
+    expect(getEffectiveRuntimeRoomMode('dc:explicit-tribunal')).toBe('single');
+    expect(isPairedRoomJid('dc:explicit-tribunal')).toBe(false);
 
     clearExplicitRoomMode('dc:explicit-tribunal');
 
     expect(getExplicitRoomMode('dc:explicit-tribunal')).toBeUndefined();
     expect(getEffectiveRoomMode('dc:explicit-tribunal')).toBe('single');
+    expect(getEffectiveRuntimeRoomMode('dc:explicit-tribunal')).toBe('single');
     expect(isPairedRoomJid('dc:explicit-tribunal')).toBe(false);
   });
 });

src/db.ts

@@ -1978,8 +1978,15 @@ export function getEffectiveRoomMode(chatJid: string): RoomMode {
   return getExplicitRoomMode(chatJid) ?? inferRoomModeForJid(chatJid);
 }
 
+export function getEffectiveRuntimeRoomMode(chatJid: string): RoomMode {
+  return getEffectiveRoomMode(chatJid) === 'tribunal' &&
+    inferRoomModeForJid(chatJid) === 'tribunal'
+    ? 'tribunal'
+    : 'single';
+}
+
 export function isPairedRoomJid(jid: string): boolean {
-  return getEffectiveRoomMode(jid) === 'tribunal';
+  return getEffectiveRuntimeRoomMode(jid) === 'tribunal';
 }
 
 // --- Paired task/project/workspace state ---

src/service-routing.test.ts

@@ -108,7 +108,7 @@ describe('service-routing global failover', () => {
     });
   });
 
-  it('uses explicit tribunal room mode to add reviewer lease on solo rooms', () => {
+  it('does not create reviewer lease for explicit tribunal without dual registration capability', () => {
     setRegisteredGroup('dc:explicit-tribunal', {
       name: 'Explicit Tribunal Claude',
       folder: 'explicit-tribunal-claude',
@@ -121,7 +121,7 @@ describe('service-routing global failover', () => {
     expect(getEffectiveChannelLease('dc:explicit-tribunal')).toMatchObject({
       chat_jid: 'dc:explicit-tribunal',
       owner_service_id: 'claude',
-      reviewer_service_id: 'claude',
+      reviewer_service_id: null,
       explicit: false,
     });
   });

src/service-routing.ts

@@ -12,7 +12,7 @@ import {
 import {
   clearChannelOwnerLease,
   getAllChannelOwnerLeases,
-  getEffectiveRoomMode,
+  getEffectiveRuntimeRoomMode,
   getRegisteredAgentTypesForJid,
   setChannelOwnerLease,
   type ChannelOwnerLeaseRow,
@@ -59,7 +59,7 @@ function getDefaultLease(chatJid: string): EffectiveChannelLease {
   const types = getRegisteredAgentTypesForJid(chatJid);
   const hasClaude = types.includes('claude-code');
   const hasCodex = types.includes('codex');
-  const roomMode = getEffectiveRoomMode(chatJid);
+  const roomMode = getEffectiveRuntimeRoomMode(chatJid);
 
   if (roomMode === 'tribunal') {
     const ownerServiceId =