fix(kiloclaw): reverse region list on capacity recovery instead of deprioritizing

deprioritizeRegion compared the concrete region (e.g. 'ord') against
meta-regions ('us', 'eu'), so it never matched and the recovery volume
landed back in the same exhausted region. Reverse the configured region
list instead so recovery deterministically tries the opposite geographic
region first.

Author: pandemicsyn

kiloclaw/src/durable-objects/kiloclaw-instance.test.ts

@@ -2128,7 +2128,7 @@ describe('start: volume region validation', () => {
 // ============================================================================
 
 describe('start: 412 insufficient resources recovery', () => {
-  it('fresh provision (never started): deletes volume and creates fresh with deprioritized regions', async () => {
+  it('fresh provision (never started): deletes volume and creates fresh with reversed regions', async () => {
     const { instance, storage } = createInstance();
     await seedProvisioned(storage, { flyMachineId: null, lastStartedAt: null });
 
@@ -2150,16 +2150,15 @@ describe('start: 412 insufficient resources recovery', () => {
 
     // Old volume was deleted
     expect(flyClient.deleteVolume).toHaveBeenCalledWith(expect.anything(), 'vol-1');
-    // New volume created via fallback with deprioritized regions and compute hint
+    // New volume created via fallback with reversed regions and compute hint
     const regions412Call = (flyClient.createVolumeWithFallback as Mock).mock.calls[0];
     expect(regions412Call[1]).toEqual(
       expect.objectContaining({
         compute: expect.objectContaining({ cpus: 2, memory_mb: 3072 }) as unknown,
       })
     );
-    // Regions are shuffled, so just check the set (deprioritize is a no-op here
-    // because 'iad' is not in FLY_REGION='us,eu')
-    expect((regions412Call[2] as string[]).sort()).toEqual(['eu', 'us']);
+    // Regions are reversed from FLY_REGION='us,eu' so EU is tried first on recovery
+    expect(regions412Call[2]).toEqual(['eu', 'us']);
     // source_volume_id should NOT be set for fresh provision
     const createVolumeCall = (flyClient.createVolumeWithFallback as Mock).mock
       .calls[0][1] as Record<string, unknown>;
@@ -2197,16 +2196,16 @@ describe('start: 412 insufficient resources recovery', () => {
 
     await instance.start('user-1');
 
-    // Volume was forked (source_volume_id set) with compute hint and deprioritized regions
+    // Volume was forked (source_volume_id set) with compute hint and reversed regions
     const regionsForkCall = (flyClient.createVolumeWithFallback as Mock).mock.calls[0];
     expect(regionsForkCall[1]).toEqual(
       expect.objectContaining({
         source_volume_id: 'vol-1',
         compute: expect.objectContaining({ cpus: 2, memory_mb: 3072 }) as unknown,
       })
     );
-    // Regions are shuffled — check the set
-    expect((regionsForkCall[2] as string[]).sort()).toEqual(['eu', 'us']);
+    // Regions are reversed from FLY_REGION='us,eu' so EU is tried first on recovery
+    expect(regionsForkCall[2]).toEqual(['eu', 'us']);
     // Old volume was deleted
     expect(flyClient.deleteVolume).toHaveBeenCalledWith(expect.anything(), 'vol-1');
     // Machine was retried
@@ -2270,8 +2269,8 @@ describe('start: 412 insufficient resources recovery', () => {
         compute: expect.objectContaining({ cpus: 2, memory_mb: 3072 }) as unknown,
       })
     );
-    // Regions are shuffled then deprioritized — check the set
-    expect((regionsUpdateCall[2] as string[]).sort()).toEqual(['eu', 'us']);
+    // Regions are reversed from FLY_REGION='us,eu' so EU is tried first on recovery
+    expect(regionsUpdateCall[2]).toEqual(['eu', 'us']);
     // New machine was created
     expect(storage._store.get('flyMachineId')).toBe('machine-new');
     expect(storage._store.get('flyVolumeId')).toBe('vol-new');

kiloclaw/src/durable-objects/kiloclaw-instance/fly-machines.ts

@@ -8,7 +8,7 @@ import {
   DEFAULT_FLY_REGION,
   STALE_PROVISION_THRESHOLD_MS,
 } from '../../config';
-import { parseRegions, shuffleRegions, deprioritizeRegion } from '../regions';
+import { parseRegions, shuffleRegions } from '../regions';
 import { guestFromSize, volumeNameFromSandboxId } from '../machine-config';
 import type { InstanceMutableState } from './types';
 import { storageUpdate } from './state';
@@ -65,8 +65,7 @@ export async function replaceStrandedVolume(
   const oldVolumeId = state.flyVolumeId;
   const oldRegion = state.flyRegion;
   const hasUserData = state.lastStartedAt !== null;
-  const allRegions = shuffleRegions(parseRegions(env.FLY_REGION ?? DEFAULT_FLY_REGION));
-  const regions = deprioritizeRegion(allRegions, oldRegion);
+  const regions = parseRegions(env.FLY_REGION ?? DEFAULT_FLY_REGION).reverse();
   const compute = guestFromSize(state.machineSize);
 
   // Destroy existing machine if any — it's stuck on the constrained host.