ipn,tailfs: tie TailFS share configuration to user profile

Previously, the configuration of which folders to share persisted across
profile changes. Now, it is tied to the user's profile.

Updates tailscale/corp#16827

Signed-off-by: Percy Wegmann <percy@tailscale.com>

ipn/ipn_clone.go

@@ -10,6 +10,7 @@ import (
 	"net/netip"
 
 	"tailscale.com/tailcfg"
+	"tailscale.com/tailfs"
 	"tailscale.com/types/persist"
 	"tailscale.com/types/preftype"
 )
@@ -24,6 +25,12 @@ func (src *Prefs) Clone() *Prefs {
 	*dst = *src
 	dst.AdvertiseTags = append(src.AdvertiseTags[:0:0], src.AdvertiseTags...)
 	dst.AdvertiseRoutes = append(src.AdvertiseRoutes[:0:0], src.AdvertiseRoutes...)
+	if src.TailFSShares != nil {
+		dst.TailFSShares = make([]*tailfs.Share, len(src.TailFSShares))
+		for i := range dst.TailFSShares {
+			dst.TailFSShares[i] = src.TailFSShares[i].Clone()
+		}
+	}
 	dst.Persist = src.Persist.Clone()
 	return dst
 }
@@ -56,6 +63,7 @@ var _PrefsCloneNeedsRegeneration = Prefs(struct {
 	AppConnector           AppConnectorPrefs
 	PostureChecking        bool
 	NetfilterKind          string
+	TailFSShares           []*tailfs.Share
 	Persist                *persist.Persist
 }{})