chore: genericize deployment-specific defaults for public release

- core compose: parameterize TZ (default Etc/UTC), restic S3 region+endpoint
  (vendor-neutral default: AWS S3 us-east-1, no custom endpoint), and the
  xray-enclave allowlist (APEX_ENCLAVE_SUBNET, default 198.18.0.0/16).
  Cloudflare + resticontainer kept as-is.
- the reference fleet pins its real values (Europe/Moscow, ru-central1, Yandex
  Object Storage) in each node's apex.env, so deployed behavior is unchanged.
- drop PARITY.md (internal bash->python port audit; node-specific narrative).
- genericize node-name leftovers (icarus/daedalus, MSK) in tests + comments.

Tests: 26/26 pass. Verified: resticontainer resolves ru-central1/Yandex/Moscow on a node.

tests/test_tpl.py

@@ -15,8 +15,8 @@ class TestTpl(unittest.TestCase):
 
     def test_render_substitutes_known_vars(self):
         self._w("cron/crontab", "root=${APEX_TIER1} node=$APEX_NODE\n")
-        out = self.tpl.render("cron/crontab", {"APEX_TIER1": "/mnt/t1", "APEX_NODE": "daedalus"})
-        self.assertEqual(out, "root=/mnt/t1 node=daedalus\n")
+        out = self.tpl.render("cron/crontab", {"APEX_TIER1": "/mnt/t1", "APEX_NODE": "node1"})
+        self.assertEqual(out, "root=/mnt/t1 node=node1\n")
 
     def test_render_leaves_shell_command_substitution(self):
         self._w("c", "x $(cat /f) ${APEX_NODE}\n")