feat(billing): service API-key generation + matching

Add _match_api_key() class method to fusion.billing.service, with a
TDD test suite (TestServiceApiKey) covering key generation, hash storage,
positive match, and rejection of bad/inactive keys. Also fix
fcb_test_on_trial.sh to use --http-port 8070, as Odoo 19 forces
http_spawn() even under --no-http when --test-enable is set.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

fusion_centralize_billing/models/service.py

@@ -54,3 +54,11 @@ class FusionBillingService(models.Model):
         raw = secrets.token_urlsafe(32)
         self.api_key_hash = hashlib.sha256(raw.encode()).hexdigest()
         return raw
+
+    @api.model
+    def _match_api_key(self, raw_key):
+        """Return the active service whose stored hash matches raw_key, else empty recordset."""
+        if not raw_key:
+            return self.browse()
+        key_hash = hashlib.sha256(raw_key.encode()).hexdigest()
+        return self.search([('api_key_hash', '=', key_hash), ('active', '=', True)], limit=1)