Add Agent Context API for external agent integration

Phase 1: Authentication and read-only context
- POST /agent/auth/request - request access with name + agent_id
- GET /agent/auth/poll - poll for approval status
- POST /agent/auth/approve|deny - user approval (browser auth required)
- GET /agent/context - 7-day timeline context (agent session required)

Phase 1.5: Browser-only agent endpoints (HTML pages)
- GET /agent/web/request - request page with token
- GET /agent/web/status - status page with polling
- GET /agent/web/context - context page with timeline data

WebSocket notifications:
- GET /ws/notifications - push agent requests to browsers
- Approval modal with trust indicators and countdown timer

Database:
- agents table for registered agent tracking
- agent_sessions table for pending/active sessions

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

1 files changed, 51 insertions, 0 deletions

diff --git a/internal/models/types.go b/internal/models/types.go
index 4bf8462..5214bf8 100644
--- a/internal/models/types.go
+++ b/internal/models/types.go
@@ -146,3 +146,54 @@ type DashboardData struct {
 	LastUpdated time.Time       `json:"last_updated"`
 	Errors      []string        `json:"errors,omitempty"`
 }
+
+// Agent represents a registered external agent
+type Agent struct {
+	ID        int64      `json:"id"`
+	Name      string     `json:"name"`
+	AgentID   string     `json:"agent_id"` // UUID from agent
+	CreatedAt time.Time  `json:"created_at"`
+	LastSeen  *time.Time `json:"last_seen,omitempty"`
+	Trusted   bool       `json:"trusted"`
+}
+
+// AgentSession represents a pending request or active session
+type AgentSession struct {
+	ID               int64      `json:"id"`
+	RequestToken     string     `json:"request_token"`
+	AgentName        string     `json:"agent_name"`
+	AgentID          string     `json:"agent_id"`
+	Status           string     `json:"status"` // pending, approved, denied, expired
+	CreatedAt        time.Time  `json:"created_at"`
+	ExpiresAt        time.Time  `json:"expires_at"`
+	SessionToken     string     `json:"session_token,omitempty"`
+	SessionExpiresAt *time.Time `json:"session_expires_at,omitempty"`
+}
+
+// AgentAuthRequest is the request body for agent auth
+type AgentAuthRequest struct {
+	Name    string `json:"name"`
+	AgentID string `json:"agent_id"`
+}
+
+// AgentAuthResponse is the response for auth request
+type AgentAuthResponse struct {
+	RequestToken string `json:"request_token"`
+	Status       string `json:"status"`
+}
+
+// AgentPollResponse is the response for poll endpoint
+type AgentPollResponse struct {
+	Status       string     `json:"status"`
+	SessionToken string     `json:"session_token,omitempty"`
+	ExpiresAt    *time.Time `json:"expires_at,omitempty"`
+}
+
+// AgentTrustLevel indicates the trust state of an agent
+type AgentTrustLevel string
+
+const (
+	AgentTrustNew        AgentTrustLevel = "new"
+	AgentTrustRecognized AgentTrustLevel = "recognized"
+	AgentTrustSuspicious AgentTrustLevel = "suspicious"
+)