fix(paired): cap consecutive reviewer silent-failure retries

The reviewer (codex) sometimes emits a final result with no visible text.
The runtime marks the run failed → handleFailedReviewerExecution
preserves status as review_ready → the follow-up scheduler re-queues
another reviewer-turn → loop. The existing round_trip / arbiter caps
never fire because round_trip_count only advances on owner-side
submissions; bot-side reviewer flakes never increment it.

Mirror the owner_failure_count pattern: add reviewer_failure_count to
paired_tasks, increment on each silent failure, and escalate via
requestArbiterOrEscalate once it reaches 2. Reset to 0 on every
successful reviewer completion path (PROCEED/REVISE/arbiter/wait-for-user)
and when the owner re-submits a fresh review cycle.

Repro chat: 1507762222724546560 (stock-adiviser). Task
33968d31-0da2-480c-85d3-7a3999822ab4 logged 11 consecutive
reviewer-turn entries with no work_items and round_trip_count stuck
at 1.

src/db/base-schema.ts

@@ -121,6 +121,7 @@ export function applyBaseSchema(database: Database): void {
       review_requested_at TEXT,
       round_trip_count INTEGER NOT NULL DEFAULT 0,
       owner_failure_count INTEGER NOT NULL DEFAULT 0,
+      reviewer_failure_count INTEGER NOT NULL DEFAULT 0,
       owner_step_done_streak INTEGER NOT NULL DEFAULT 0,
       finalize_step_done_count INTEGER NOT NULL DEFAULT 0,
       task_done_then_user_reopen_count INTEGER NOT NULL DEFAULT 0,

src/db/bootstrap.test.ts

@@ -39,6 +39,7 @@ function getExpectedSchemaMigrations(): Array<{
     { version: 12, name: 'paired_verdict_and_step_telemetry' },
     { version: 13, name: 'message_source_kind' },
     { version: 14, name: 'work_item_attachments' },
+    { version: 15, name: 'reviewer_failure_count' },
   ];
 }
 

src/db/migrations/015_reviewer-failure-count.ts

@@ -0,0 +1,23 @@
+import type { Database } from 'bun:sqlite';
+
+import { tableHasColumn } from './helpers.js';
+import type { SchemaMigrationDefinition } from './types.js';
+
+export const REVIEWER_FAILURE_COUNT_MIGRATION: SchemaMigrationDefinition = {
+  version: 15,
+  name: 'reviewer_failure_count',
+  apply(database: Database) {
+    if (!tableHasColumn(database, 'paired_tasks', 'reviewer_failure_count')) {
+      database.exec(`
+        ALTER TABLE paired_tasks
+        ADD COLUMN reviewer_failure_count INTEGER NOT NULL DEFAULT 0
+      `);
+    }
+
+    database.exec(`
+      UPDATE paired_tasks
+         SET reviewer_failure_count = 0
+       WHERE reviewer_failure_count IS NULL
+    `);
+  },
+};

src/db/migrations/index.ts

@@ -14,6 +14,7 @@ import { OWNER_FAILURE_COUNT_MIGRATION } from './011_owner-failure-count.js';
 import { PAIRED_VERDICT_AND_STEP_TELEMETRY_MIGRATION } from './012_paired-verdict-and-step-telemetry.js';
 import { MESSAGE_SOURCE_KIND_MIGRATION } from './013_message-source-kind.js';
 import { WORK_ITEM_ATTACHMENTS_MIGRATION } from './014_work-item-attachments.js';
+import { REVIEWER_FAILURE_COUNT_MIGRATION } from './015_reviewer-failure-count.js';
 import type {
   SchemaMigrationArgs,
   SchemaMigrationDefinition,
@@ -36,6 +37,7 @@ const ORDERED_SCHEMA_MIGRATIONS: readonly SchemaMigrationDefinition[] = [
   PAIRED_VERDICT_AND_STEP_TELEMETRY_MIGRATION,
   MESSAGE_SOURCE_KIND_MIGRATION,
   WORK_ITEM_ATTACHMENTS_MIGRATION,
+  REVIEWER_FAILURE_COUNT_MIGRATION,
 ];
 
 function ensureSchemaMigrationsTable(database: Database): void {

src/db/paired-state.ts

@@ -51,6 +51,7 @@ export type PairedTaskUpdates = Partial<
     | 'review_requested_at'
     | 'round_trip_count'
     | 'owner_failure_count'
+    | 'reviewer_failure_count'
     | 'owner_step_done_streak'
     | 'finalize_step_done_count'
     | 'task_done_then_user_reopen_count'
@@ -177,6 +178,7 @@ export function createPairedTaskInDatabase(
           review_requested_at,
           round_trip_count,
           owner_failure_count,
+          reviewer_failure_count,
           owner_step_done_streak,
           finalize_step_done_count,
           task_done_then_user_reopen_count,
@@ -188,7 +190,7 @@ export function createPairedTaskInDatabase(
           created_at,
           updated_at
         )
-        VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
+        VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?)
       `,
     )
     .run(
@@ -206,6 +208,7 @@ export function createPairedTaskInDatabase(
       task.review_requested_at,
       task.round_trip_count,
       task.owner_failure_count ?? 0,
+      task.reviewer_failure_count ?? 0,
       task.owner_step_done_streak ?? 0,
       task.finalize_step_done_count ?? 0,
       task.task_done_then_user_reopen_count ?? 0,
@@ -318,6 +321,10 @@ export function updatePairedTaskInDatabase(
     fields.push('owner_failure_count = ?');
     values.push(updates.owner_failure_count);
   }
+  if (updates.reviewer_failure_count !== undefined) {
+    fields.push('reviewer_failure_count = ?');
+    values.push(updates.reviewer_failure_count);
+  }
   if (updates.owner_step_done_streak !== undefined) {
     fields.push('owner_step_done_streak = ?');
     values.push(updates.owner_step_done_streak);
@@ -397,6 +404,10 @@ export function updatePairedTaskIfUnchangedInDatabase(
     fields.push('owner_failure_count = ?');
     values.push(updates.owner_failure_count);
   }
+  if (updates.reviewer_failure_count !== undefined) {
+    fields.push('reviewer_failure_count = ?');
+    values.push(updates.reviewer_failure_count);
+  }
   if (updates.owner_step_done_streak !== undefined) {
     fields.push('owner_step_done_streak = ?');
     values.push(updates.owner_step_done_streak);