test(state): force the grace-boundary ages in the moved lock property

The moved property is named for the grace boundary but drew ageMs and graceMs
as two independent durations, so ageMs === graceMs was almost never sampled and
the >= boundary went untested. Relaxing the classifier from >= to > at
mcp-lifecycle-lock-identity.ts:210 still passed 15/15 before this change.

Test ages graceMs - 1, graceMs, and graceMs + 1 alongside the random age, which
keeps the broad coverage the random draw gave. The >= mutation now fails.

Reported by CodeRabbit on #8436.

Refs: #8356
Signed-off-by: harjoth <harjoth.khara@gmail.com>

Author: harjothkhara

src/lib/state/mcp-lifecycle-lock-identity.test.ts

@@ -399,15 +399,19 @@ describe("MCP lifecycle lock identity properties", () => {
             },
           });
 
-          expect(
-            classifyMcpLifecycleLock(
-              observation(lockOwner, 0),
-              SANDBOX_NAME,
-              ageMs,
-              graceMs,
-              localProbes,
-            ),
-          ).toBe(ageMs >= graceMs ? "stale" : "wait");
+          // Two independent durations almost never land on ageMs === graceMs, so
+          // the boundary this property is named for needs the exact ages forced.
+          for (const boundaryAgeMs of [graceMs - 1, graceMs, graceMs + 1, ageMs]) {
+            expect(
+              classifyMcpLifecycleLock(
+                observation(lockOwner, 0),
+                SANDBOX_NAME,
+                boundaryAgeMs,
+                graceMs,
+                localProbes,
+              ),
+            ).toBe(boundaryAgeMs >= graceMs ? "stale" : "wait");
+          }
         },
       ),
       SEEDED_PROPERTY_PARAMETERS,