feat(pairing): optional token TTL + revoke endpoint (#9/#12, #22)

Builds on the seed-URL pairing in #21 (stacked).

(b) TTL — PairMachineData.duration_hours (validated > 0) threads through
    pair_spire -> create_new_token (lnbits#55). None = non-expiring.

(c) Revoke — POST /machines/{id}/revoke -> revoke_spire ->
    admin_client.revoke_key_user(spire-<id>). Per spirekeeper#22, revoke
    MUST go through KeyUser.revokedAt (revoke_key_user), NOT token revoke:
    lnbits eager-binds (redeems) the connect token at provision, so
    nsecbunkerd has materialised the policy into per-KeyUser grants its
    ACL checks BEFORE the Token.revokedAt filter -> token revoke is a
    silent no-op. Returns RevokeResult{revoked_count}: >=1 = cut, 0 =
    never bound. set_machine_unpaired clears paired_at (keeps npub +
    bunker_spire_key_name for audit / re-pair).

7 new tests (duration threading + default-None; revoke routes to
revoke_key_user and never token-revoke + error mapping; endpoint wiring
revoke happy/zero/502). 210 green; new code black/ruff-clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/test_pairing.py

@@ -16,6 +16,7 @@ import json
 from datetime import datetime, timezone
 
 import pytest
+from lnbits.core.services.nsec_bunker import NsecBunkerError
 from lnbits.utils.nostr import hex_to_npub
 
 from ..models import Machine
@@ -27,6 +28,7 @@ from ..pairing import (
     PairingError,
     build_seed_url,
     pair_spire,
+    revoke_spire,
     spire_key_name,
 )
 
@@ -70,9 +72,10 @@ class FakeBunker:
     admin_pubkey = "fake-admin-pubkey"
 
     # pragma: allowlist secret
-    def __init__(self, *, policies=None, token_secret="s3cr3t"):
+    def __init__(self, *, policies=None, token_secret="s3cr3t", revoke_count=1):
         self._policies = policies or []
         self._token_secret = token_secret
+        self._revoke_count = revoke_count
         self.calls: list[tuple] = []
         self._next_policy_id = 7
 
@@ -93,8 +96,16 @@ class FakeBunker:
     async def add_policy_rule(self, policy_id, rule):
         self.calls.append(("add_policy_rule", policy_id, rule))
 
-    async def create_new_token(self, key_name, client_name, policy_id):
-        self.calls.append(("create_new_token", key_name, client_name, policy_id))
+    async def create_new_token(
+        self, key_name, client_name, policy_id, duration_hours=None
+    ):
+        self.calls.append(
+            ("create_new_token", key_name, client_name, policy_id, duration_hours)
+        )
+
+    async def revoke_key_user(self, key_name):
+        self.calls.append(("revoke_key_user", key_name))
+        return self._revoke_count
 
     async def get_key_tokens(self, key_name):
         self.calls.append(("get_key_tokens", key_name))
@@ -251,3 +262,46 @@ def test_build_seed_url_roundtrip():
     payload = json.loads(base64.urlsafe_b64decode(blob + "=" * (-len(blob) % 4)))
     assert payload["spire_pubkey"] == _SPIRE_HEX
     assert payload["relays"] == _RELAYS
+
+
+def test_pair_threads_duration_hours():
+    bunker = FakeBunker()
+    asyncio.run(
+        pair_spire(
+            _machine(),
+            relays=_RELAYS,
+            admin_client=bunker,
+            bunker_relay=_BUNKER_RELAY,
+            keystore_passphrase=_PASSPHRASE,
+            duration_hours=720,
+        )
+    )
+    # create_new_token tuple is (name, key, client, policy_id, duration_hours)
+    assert bunker.named("create_new_token")[0][4] == 720
+
+
+def test_pair_default_duration_is_none():
+    bunker = FakeBunker()
+    _pair(bunker)  # no duration_hours
+    assert bunker.named("create_new_token")[0][4] is None
+
+
+def test_revoke_spire_calls_revoke_key_user():
+    # revoke MUST go through revoke_key_user (KeyUser.revokedAt), not token
+    # revoke — token revoke is a no-op once redeemed (spirekeeper#22).
+    bunker = FakeBunker(revoke_count=2)
+    count = asyncio.run(revoke_spire(_machine(), admin_client=bunker))
+    assert count == 2
+    assert bunker.named("revoke_key_user") == [("revoke_key_user", "spire-m1")]
+    assert not bunker.named("revoke_token")  # never token-revoke
+
+
+def test_revoke_spire_maps_bunker_error():
+    bunker = FakeBunker()
+
+    async def _boom(key_name):
+        raise NsecBunkerError("nope")
+
+    bunker.revoke_key_user = _boom
+    with pytest.raises(PairingError, match="revoke"):
+        asyncio.run(revoke_spire(_machine(), admin_client=bunker))