Generate tracker policy document from banner snapshot

Add a markdown "Cookie and Tracking Technologies Policy" template in
the policy-writer tone that covers cookies and other tracking
technologies, with GDPR, UK GDPR, FADP, and CCPA/CPRA privacy-rights
framing. Convert it to ProseMirror JSON and add PublishTrackerPolicy,
which builds the document from a banner's latest published version
snapshot and its tracker third parties. The document is GENERATED and
private in the trust center, linked to the banner via
policy_document_id.

Add CookieItem.HumanizedDuration so server-rendered lifetimes match the
banner's humanizeDuration helper, and reword the publish trigger and
backfill comment to reflect the broader tracker scope.

Signed-off-by: Émile Ré <emile@probo.com>

pkg/docgen/generator.go

@@ -469,6 +469,35 @@ type (
 		ValidFrom  string
 		ValidUntil string
 	}
+
+	TrackerPolicyData struct {
+		OrganizationName  string
+		WebsiteOrigin     string
+		GeneratedAt       time.Time
+		PrivacyPolicyURL  string
+		ConsentExpiryDays int
+		Categories        []TrackerPolicyCategory
+		ThirdParties      []TrackerPolicyThirdParty
+	}
+
+	TrackerPolicyCategory struct {
+		Name        string
+		Description string
+		Necessary   bool
+		Trackers    []TrackerPolicyTracker
+	}
+
+	TrackerPolicyTracker struct {
+		Name     string
+		Purpose  string
+		Duration string
+	}
+
+	TrackerPolicyThirdParty struct {
+		Name             string
+		Description      string
+		PrivacyPolicyURL string
+	}
 )
 
 func BoolLabel(v bool) string {