feat: rework auth model with UserToken and Daedalus/Pallas integration

- Rename MCPToken to UserToken across models, views, and tests
- Update URL names from mcp-token-* to token-*
- Add Daedalus/Pallas integration design doc (v2)
- Switch docker-compose to build local mnemosyne:local image via shared
  build config instead of pulling from git.helu.ca

mnemosyne/mcp_server/tests/test_models.py

@@ -1,10 +1,10 @@
 """Tests for the Team / LibraryMembership / TeamWorkspaceAssignment models.
 
-``MCPToken``'s hash-at-rest semantics live in ``test_token.py``; this
+``UserToken``'s hash-at-rest semantics live in ``test_token.py``; this
 module exercises the new Phase 2 tables introduced by
 ``docs/DAEDALUS_PALLAS_INTEGRATION_v1.md`` §4 plus the
 ``allowed_libraries`` JSONField attached to the existing
-:class:`~mcp_server.models.MCPToken`.
+:class:`~mcp_server.models.UserToken`.
 """
 
 from __future__ import annotations
@@ -18,7 +18,7 @@ from django.test import TestCase
 from mcp_server.models import (
     LibraryMembership,
     MCPSigningKey,
-    MCPToken,
+    UserToken,
     Team,
     TeamWorkspaceAssignment,
 )
@@ -92,26 +92,26 @@ class LibraryMembershipTest(TestCase):
 
 
 # ---------------------------------------------------------------------------
-# MCPToken.allowed_libraries
+# UserToken.allowed_libraries
 # ---------------------------------------------------------------------------
 
 
-class MCPTokenAllowedLibrariesTest(TestCase):
+class UserTokenAllowedLibrariesTest(TestCase):
     def setUp(self):
         self.user = User.objects.create_user(username="u", password="pw")
 
     def test_defaults_to_empty_list(self):
-        token, _ = MCPToken.objects.create_token(user=self.user, name="t")
+        token, _ = UserToken.objects.create_token(user=self.user, name="t")
         self.assertEqual(token.allowed_libraries, [])
 
     def test_create_token_accepts_allowed_libraries(self):
-        token, _ = MCPToken.objects.create_token(
+        token, _ = UserToken.objects.create_token(
             user=self.user, name="t", allowed_libraries=["lib-a", "lib-b"]
         )
         self.assertEqual(token.allowed_libraries, ["lib-a", "lib-b"])
 
     def test_allowed_libraries_round_trips(self):
-        token, _ = MCPToken.objects.create_token(
+        token, _ = UserToken.objects.create_token(
             user=self.user,
             name="t",
             allowed_libraries=["lib-a", "lib-b", "lib-c"],