test(relay): pin the live-record ownership fallback across owner-map eviction

The resident disjunct in stillOwnsPtyId let a PTY that outlives 4,096
admissions certify its own exit after its owner entry was evicted; nothing
checked in failed when it was removed. Round-5 review found the survivor.

config/reliability-gates.jsonc

@@ -18744,7 +18744,9 @@
             "does not certify a revived process with the exit of the one it replaced",
             "does not let a superseded incarnation certify the id once both records are gone",
             "evicts observations in the order it made them, not the order it was asked",
-            "forgets every observation when the relay restarts, even under the same mint epoch"
+            "forgets every observation when the relay restarts, even under the same mint epoch",
+            "certifies a long-lived resident whose owner entry was evicted",
+            "withholds a late observation once both the record and its owner entry are gone"
           ]
         },
         {
@@ -18790,12 +18792,12 @@
           "command": "ORCA_BACKGROUND_LAUNCH=1 node_modules/.bin/vitest run --config config/vitest.config.ts src/relay/pty-handler-liveness-probe.test.ts src/relay/pty-handler-ssh-exit-certification.test.ts src/relay/pty-handler-ssh-recovery-convergence.test.ts src/main/providers/ssh-pty-liveness-probe.test.ts src/main/providers/ssh-pty-provider-liveness-readback.test.ts src/main/runtime/runtime-legacy-worker-terminal-exit-certification.test.ts",
           "result": "passed",
           "durationSeconds": 1.27,
-          "summary": "6 files, 56 tests passed. The convergence file fails 1/3 without the owner readback; twelve mutations of the probe, its incarnation binding, the published capabilities, the bounded map and the forwarder each fail at least one of these tests."
+          "summary": "6 files, 58 tests passed. The convergence file fails 1/3 without the owner readback; thirteen mutations of the probe, its incarnation binding, the published capabilities, the bounded map and the forwarder each fail at least one of these tests."
         }
       ],
       "runtimeBudget": {
         "p95Seconds": 30,
-        "scope": "Six unit/service-level files; the ledger-eviction case drives 4,097 spawn-and-exit cycles through the real handler and reads the oldest entry before the overflow and dominates the run at roughly 0.8 s."
+        "scope": "Six unit/service-level files; the ledger-eviction and owner-eviction cases each drive 4,096+ spawn-and-exit cycles through the real handler and reads the oldest entry before the overflow and dominates the run at roughly 0.8 s."
       },
       "flakeHistory": {
         "status": "not-started",

src/relay/pty-handler-liveness-probe.test.ts

@@ -374,4 +374,50 @@ describe('PtyHandler.probeLiveness', () => {
       expect(await probe(id)).toBe('unverifiable')
     })
   })
+
+  describe('owner entries evicted from the bounded map while a record outlives them', () => {
+    async function churnOwnersPastTheCap(): Promise<void> {
+      for (let index = 0; index < OBSERVED_PTY_EXIT_HISTORY; index++) {
+        await spawnPty()
+        reportExitOfLatestPty()
+      }
+    }
+
+    function ownerEntry(id: string): string | undefined {
+      return (
+        handler as unknown as { ptyIdIncarnationOwners: { peek(key: string): string | undefined } }
+      ).ptyIdIncarnationOwners.peek(id)
+    }
+
+    it('certifies a long-lived resident whose owner entry was evicted', async () => {
+      const { id } = await spawnPty()
+      const exit = mockPtyInstance.onExit.mock.calls.at(-1)?.[0] as (event: {
+        exitCode: number
+      }) => void
+      await churnOwnersPastTheCap()
+      expect(ownerEntry(id)).toBeUndefined()
+      expect(await probe(id)).toBe('live')
+
+      // The record is still in the pool, so it speaks for the id without the owner map: a PTY
+      // that outlives 4,096 admissions must still certify its own exit.
+      exit({ exitCode: 0 })
+
+      expect(await probe(id)).toBe('exited')
+    })
+
+    it('withholds a late observation once both the record and its owner entry are gone', async () => {
+      const { id } = await spawnPty()
+      const exit = mockPtyInstance.onExit.mock.calls.at(-1)?.[0] as (event: {
+        exitCode: number
+      }) => void
+      await forgetRecordWithoutObservingItsExit(id)
+      await churnOwnersPastTheCap()
+      expect(ownerEntry(id)).toBeUndefined()
+
+      // Forgetting fails closed: with no owner to compare against, nothing may record.
+      exit({ exitCode: 0 })
+
+      expect(await probe(id)).toBe('unverifiable')
+    })
+  })
 })