fix(models): add explicit enum names to match migration types

SQLAlchemy's Enum() auto-generates type names from Python class names
(e.g., AutonomyLevel -> autonomylevel), but migrations defined them
with underscores (e.g., autonomy_level). This mismatch caused:

  "type 'autonomylevel' does not exist"

Added explicit name parameters to all enum columns to match the
migration-defined type names:
- autonomy_level, project_status, project_complexity, client_mode
- agent_status, sprint_status
- issue_type, issue_status, issue_priority, sync_status

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/app/models/syndarix/project.py

@@ -35,28 +35,28 @@ class Project(Base, UUIDMixin, TimestampMixin):
     description = Column(Text, nullable=True)
 
     autonomy_level: Column[AutonomyLevel] = Column(
-        Enum(AutonomyLevel),
+        Enum(AutonomyLevel, name="autonomy_level"),
         default=AutonomyLevel.MILESTONE,
         nullable=False,
         index=True,
     )
 
     status: Column[ProjectStatus] = Column(
-        Enum(ProjectStatus),
+        Enum(ProjectStatus, name="project_status"),
         default=ProjectStatus.ACTIVE,
         nullable=False,
         index=True,
     )
 
     complexity: Column[ProjectComplexity] = Column(
-        Enum(ProjectComplexity),
+        Enum(ProjectComplexity, name="project_complexity"),
         default=ProjectComplexity.MEDIUM,
         nullable=False,
         index=True,
     )
 
     client_mode: Column[ClientMode] = Column(
-        Enum(ClientMode),
+        Enum(ClientMode, name="client_mode"),
         default=ClientMode.AUTO,
         nullable=False,
         index=True,