feat(models): widen Site struct and DB schema for ping, port, dns, group monitor types

Add Hostname, Port, Timeout, Method, Description, ParentID, AcceptedCodes,
DNSResolveType, DNSServer, and IgnoreTLS fields. Refactor AddSite/UpdateSite
to accept models.Site instead of individual params. Includes DB migrations
for existing databases, per-monitor timeout/TLS in the engine, new type
options in TUI forms, and TYPE column in the sites table.

internal/models/models.go

@@ -6,23 +6,33 @@ type Site struct {
 	ID              int
 	Name            string
 	URL             string
-	Type            string // "http" or "push"
-	Token           string // Secure Token
+	Type            string // "http", "push", "ping", "port", "dns", "group"
+	Token           string
 	Interval        int
 	AlertID         int
 	CheckSSL        bool
 	ExpiryThreshold int
-	
 	MaxRetries      int
-	FailureCount    int
 
-	Status          string
-	StatusCode      int
-	Latency         time.Duration
-	CertExpiry      time.Time
-	HasSSL          bool
-	LastCheck       time.Time
-	SentSSLWarning  bool 
+	Hostname       string
+	Port           int
+	Timeout        int
+	Method         string
+	Description    string
+	ParentID       int
+	AcceptedCodes  string
+	DNSResolveType string
+	DNSServer      string
+	IgnoreTLS      bool
+
+	FailureCount   int
+	Status         string
+	StatusCode     int
+	Latency        time.Duration
+	CertExpiry     time.Time
+	HasSSL         bool
+	LastCheck      time.Time
+	SentSSLWarning bool
 }
 
 type AlertConfig struct {
@@ -36,7 +46,7 @@ type User struct {
 	ID        int
 	Username  string
 	PublicKey string
-	Role      string 
+	Role      string
 }
 
 // Phase 5: Backup Structure
@@ -44,4 +54,4 @@ type Backup struct {
 	Sites  []Site        `json:"sites"`
 	Alerts []AlertConfig `json:"alerts"`
 	Users  []User        `json:"users"`
-}
+}