fix: what the batch C review found

- A redirect followed for a custom base URL (quota on) no longer carries
  the user's key or cookies to another origin, as fetch itself does, and
  a private address may redirect to another private one (already counted).
- The admin Test of an Ollama or Vertex AI entry without a URL goes where
  chat sends that entry's key: the environment's own URL variable, for
  Ollama else the local default. The Test of an Ollama Cloud key without
  a URL went to the cloud while chat went to local Ollama.
- Chat saves: each save notes the chat on screen and the order of the
  reads before reading its data. A save read before switching chats no
  longer writes into the chat switched to, and a copy that waited for its
  thumbnail no longer replaces a newer one.
- "Continue without saving" keeps its button when a later auto-save fails,
  and goes away when a new message is sent.
- A screenshot check that was waiting for its image when the user pressed
  Stop stays skipped after the next message.
- MCP History: draw.io's own copy of a diagram (after get_diagram) no
  longer adds an entry without a picture; a change of background is still
  its own version. The tab ignores an edit's answer that arrives after a
  newer AI write loaded.
- Desktop: a deleted preset is not brought back by a failed switch, and a
  request naming no preset does not stop a rollback. An origin keeping
  an access code counts as having settings.
- .env: a quoted value ending in a backslash ("C:\dir\") is read as dotenv
  reads it.
- The tool card no longer crashes on an id that does not turn into text;
  an older Test's success timer no longer ends a newer Test's spinner.
- Tests that passed without their fix now check it.

electron/main/app-menu.ts

@@ -44,12 +44,12 @@ let lastSwitch = 0
 export async function switchPreset(
     id: string,
 ): Promise<Record<string, string>> {
-    const switchNumber = ++lastSwitch
     const previousPresetId = getCurrentPresetId()
     const env = applyPresetToEnv(id)
     if (!env) {
         throw new Error("Preset not found")
     }
+    const switchNumber = ++lastSwitch
     rebuildAppMenu()
 
     // In development, scripts/electron-dev.mjs restarts the Next.js dev server
@@ -64,9 +64,10 @@ export async function switchPreset(
         console.error("Failed to restart server:", error)
         const reason = error instanceof Error ? error.message : String(error)
 
-        // A newer switch started meanwhile (also of this same preset): its
-        // own restart follows, and undoing would lose that choice
-        if (switchNumber !== lastSwitch) {
+        // A newer switch started meanwhile (also of this same preset), or
+        // the preset was deleted: its own restart follows, and undoing
+        // would lose that choice
+        if (switchNumber !== lastSwitch || getCurrentPresetId() !== id) {
             throw new Error(
                 `The server could not be restarted.\n\nError: ${reason}`,
             )

electron/main/env-loader.ts

@@ -31,15 +31,20 @@ export function loadEnvFile(): void {
 /**
  * Index of the quote that closes a value starting with a quote, or -1. A
  * backslash before the quote character escapes it, as in dotenv; the
- * backslash stays in the value.
+ * backslash stays in the value. As in dotenv, an escaped quote with only a
+ * comment or nothing after it still closes the value when no other quote
+ * does ("C:\dir\" keeps its trailing backslash).
  */
 function findClosingQuote(value: string): number {
     const quote = value[0]
+    let lastEscaped = -1
     for (let i = 1; i < value.length; i++) {
-        if (value[i] === "\\" && value[i + 1] === quote) i++
-        else if (value[i] === quote) return i
+        if (value[i] === "\\" && value[i + 1] === quote) {
+            i++
+            if (/^\s*(#.*)?$/.test(value.slice(i + 1))) lastEscaped = i
+        } else if (value[i] === quote) return i
     }
-    return -1
+    return lastEscaped
 }
 
 /**