Milestone 3.6.3 — Agent Management CRUD API

GET    /v1/agents               → ListAgentsResponse (cursor-paginated)
POST   /v1/agents               → AgentResponse (201)
GET    /v1/agents/{id}          → AgentResponse
PATCH  /v1/agents/{id}          → AgentResponse
DELETE /v1/agents/{id}          → 204 No Content (soft delete)
POST   /v1/agents/{id}/activate → AgentResponse (status: active)
POST   /v1/agents/{id}/pause    → AgentResponse (status: paused)
POST   /v1/agents/{id}/archive  → AgentResponse (status: archived)

class AgentResponse(BaseModel):
    id:              UUID
    org_id:          UUID
    name:            str
    slug:            str
    status:          str   # "active", "paused", "suspended", "archived"
    config:          dict
    total_sessions:  int
    total_memories:  int
    last_active_at:  datetime | None
    created_at:      datetime
    updated_at:      datetime
 
class CreateAgentRequest(BaseModel):
    name:   str     = Field(min_length=1, max_length=255)
    slug:   str     = Field(pattern=r'^[a-z0-9-]+$', min_length=1, max_length=100)
    config: dict    = Field(default_factory=dict)
 
class PatchAgentRequest(BaseModel):
    name:   str | None = Field(None, min_length=1, max_length=255)
    config: dict | None = None
    # slug is intentionally not patchable (would break existing integrations)