feat: several models for the assistant, each with its own name, kind, address and key; a model menu in the chat when there are several (or always, from Аккаунт › Вид), the choice kept for the user

internal/server/prefs.go

@@ -4,12 +4,15 @@ import (
 	"encoding/json"
 	"net/http"
 	"strconv"
+	"strings"
 )
 
 // Each user's look of the panel (Аккаунт › Вид), kept on the server so it
 // is the same on every device: where a tab's icons go, the terminal's font
 // size, a compact file list, the time column, animations, and whether a
-// terminal or file pane opened «Здесь» starts in the active pane's folder.
+// terminal or file pane opened «Здесь» starts in the active pane's folder;
+// and the assistant's model: which one, and whether the chat always offers
+// the choice.
 type viewPrefs struct {
 	TabIcons string `json:"tabIcons,omitempty"` // left (default), right, hide
 	TermFont int    `json:"termFont,omitempty"` // 11-20; 0: the default
@@ -17,6 +20,10 @@ type viewPrefs struct {
 	FileTime string `json:"fileTime,omitempty"` // show (default), hide
 	Motion   string `json:"motion,omitempty"`   // on (default), off
 	OpenHere string `json:"openHere,omitempty"` // on (default), off
+	// AIModelPick: the model menu in the chat - when there are several
+	// (default) or always. AIModel: the id of the model chosen.
+	AIModelPick string `json:"aiModelPick,omitempty"`
+	AIModel     string `json:"aiModel,omitempty"`
 }
 
 func prefsKey(id int64) string { return "prefs_" + strconv.FormatInt(id, 10) }
@@ -38,6 +45,12 @@ func (p viewPrefs) clean() viewPrefs {
 	if p.OpenHere != "off" {
 		p.OpenHere = ""
 	}
+	if p.AIModelPick != "always" {
+		p.AIModelPick = ""
+	}
+	if len(p.AIModel) > 32 || strings.Trim(p.AIModel, "0123456789abcdefghijklmnopqrstuvwxyz") != "" {
+		p.AIModel = ""
+	}
 	return p
 }