Replace patchelf crack with Freeloader LD_PRELOAD approach

- Multi-stage Dockerfile: discover patterns from PMS binary (capstone),
  compile .so with zig (musl), layer onto lscr.io/linuxserver/plex
- Uses LD_PRELOAD instead of patchelf (which corrupts Plex's musl loader)
- Auto-discovery: broad structural patterns with string-anchored fallback
  (//feature) and relationship-based fallback (BITSET_REF within BS_INIT)
- hook.cpp uses __has_include for generated patterns with hardcoded fallbacks
- Custom wrapper.sh (no traffic_logger preload)
- Vendored Freeloader source (github.com/authrequest/Freeloader, AGPL-3.0)
- Removed stale plexmediaserver_crack.so binary
- Supports Plex 1.43.3+ (verified against 1.43.2 and 1.43.3)

Freeloader/plex_relay/tests/test_config.py

@@ -0,0 +1,44 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
+import dataclasses
+
+import pytest
+
+from plex_relay.config import RelayConfig
+from plex_relay.errors import ConfigError
+
+
+def test_valid_config_and_cache_path(tmp_path):
+    cfg = RelayConfig(token="t", ssh_user="u", data_dir=tmp_path)
+    assert cfg.cache_path == tmp_path / "relayHostKey.txt"
+    assert cfg.gating_ok() is True
+
+
+@pytest.mark.parametrize("kwargs", [
+    {"token": "", "ssh_user": "u"},
+    {"token": "t", "ssh_user": ""},
+    {"token": "t", "ssh_user": "u", "local_port": 0},
+    {"token": "t", "ssh_user": "u", "local_port": 70000},
+    {"token": "t", "ssh_user": "u", "key_ttl_seconds": 0},
+    {"token": "t", "ssh_user": "u", "reap_interval_seconds": -1},
+])
+def test_invalid_config_raises(kwargs):
+    with pytest.raises(ConfigError):
+        RelayConfig(**kwargs)
+
+
+def test_gating_requires_all_three():
+    base = dict(token="t", ssh_user="u")
+    assert RelayConfig(**base, relay_enabled=False).gating_ok() is False
+    assert RelayConfig(**base, published=False).gating_ok() is False
+    assert RelayConfig(**base, signed_in=False).gating_ok() is False
+
+
+def test_token_is_not_in_repr():
+    cfg = RelayConfig(token="SUPERSECRET", ssh_user="u")
+    assert "SUPERSECRET" not in repr(cfg)
+
+
+def test_config_is_frozen():
+    cfg = RelayConfig(token="t", ssh_user="u")
+    with pytest.raises(dataclasses.FrozenInstanceError):
+        cfg.local_port = 1  # type: ignore[misc]