# Sprint 65 Plan: Parallel Pair Upgrades and Queue Optimization

## Context

Multiple language-pair upgrades should progress concurrently without starving
high-impact work. Sprint 65 optimizes routing and queueing for pair upgrades.

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## Goals

1. Introduce pair-upgrade queue with priority classes
2. Optimize parallel execution under resource constraints
3. Prevent starvation of critical production pairs
4. Improve throughput while keeping quality gates strict

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## Steps

### Step 879: Pair-upgrade queue model (12 tests)
### Step 880: Priority policy (`critical`, `revenue`, `coverage`, `experimental`) (10 tests)
### Step 881: Parallel dispatch optimizer with dependency constraints (10 tests)
### Step 882: Starvation prevention mechanism (10 tests)
### Step 883: Queue health scoring model (10 tests)
### Step 884: Retry/backoff strategy for unstable pairs (8 tests)
### Step 885: `whetstone_enqueue_pair_upgrade` MCP tool (8 tests)
### Step 886: `whetstone_get_upgrade_queue` MCP tool (8 tests)
### Step 887: Upgrade queue observability panel model (8 tests)
### Step 888: Sprint 65 integration summary + regression (8 tests)

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## Routing Rule

- Critical-tier regressions preempt all experimental upgrades.