Revert "test(commons): make the macOS keychain probe path testable on every host"

This reverts commit 047eb197a4.

commons/src/jvmMain/kotlin/com/vitorpamplona/amethyst/commons/keystorage/SecureKeyStorage.kt

@@ -240,14 +240,6 @@ actual class SecureKeyStorage private actual constructor() {
             }
         }
 
-    /**
-     * Whether the macOS `security` CLI probe is used for strict lookups. Reads
-     * `os.name` by default; tests that wire [macSecurityLookup] set it to `true`
-     * so the probe path is exercised on every host, not only on a Mac (the
-     * vault test suite was red on Linux CI for exactly this reason).
-     */
-    internal var isMacOs: () -> Boolean = { defaultIsMacOs() }
-
     /**
      * Test seam: overridable strategy for the strict macOS lookup. Production wires
      * to [defaultMacSecurityLookup] which spawns `/usr/bin/security`. Tests replace
@@ -1015,7 +1007,7 @@ internal fun parseMacSecurityFindResult(
         }
     }
 
-private fun defaultIsMacOs(): Boolean = System.getProperty("os.name").orEmpty().startsWith("Mac")
+private fun isMacOs(): Boolean = System.getProperty("os.name").orEmpty().startsWith("Mac")
 
 /**
  * Production implementation: spawn `/usr/bin/security` and read exit code + streams.

commons/src/jvmTest/kotlin/com/vitorpamplona/amethyst/commons/keystorage/SecureKeyStorageVaultTest.kt

@@ -375,9 +375,6 @@ class SecureKeyStorageVaultTest {
         storage: SecureKeyStorage,
         backend: CountingKeyring,
     ) {
-        // Force the mac probe path regardless of the host OS: the point of the
-        // fake is to exercise it, and CI runs this suite on Linux.
-        storage.isMacOs = { true }
         storage.macSecurityLookup = { service, account ->
             backend.store[service to account]
                 ?.let { MacSecurityResult.Found(it) }