fix: rename "Add Server Manually" to "Add Custom Server" and preserve JSON key order

Rename the button and modal title from "Add Server Manually" to
"Add Custom Server" across the UI and E2E test page objects.

Enable serde_json's `preserve_order` feature so that reading and
writing back JSON config files (e.g. when removing a server) no
longer reorders unrelated keys alphabetically, preventing spurious
diffs and conflicts.

Closes #50

https://claude.ai/code/session_01V5tgbLyeWrPW5zZ1toRoPZ

Author: claude

Cargo.toml

@@ -25,7 +25,7 @@ futures = "0.3"
 
 # Serialization
 serde = { version = "1.0", features = ["derive"] }
-serde_json = "1.0"
+serde_json = { version = "1.0", features = ["preserve_order"] }
 
 # Error handling
 anyhow = "1.0"

apps/desktop/src/components/ConfigEditorModal.tsx

@@ -165,7 +165,7 @@ export function ConfigEditorModal({ spaceId, spaceName, onClose, onSaved }: Conf
         <div className="flex items-center justify-between p-4 border-b border-[rgb(var(--border))]">
           <div>
             <h3 className="text-lg font-semibold flex items-center gap-2">
-              Add Server Manually
+              Add Custom Server
             </h3>
             <p className="text-sm text-[rgb(var(--muted))]">
               Edit the JSON configuration for space: {spaceName}

apps/desktop/src/features/servers/ServersPage.tsx

@@ -787,7 +787,7 @@ export function ServersPage() {
             className="flex items-center gap-2 px-4 py-2 text-sm border border-[rgb(var(--border))] rounded-lg hover:bg-[rgb(var(--surface-hover))] transition-colors"
           >
             <FileJson className="h-4 w-4" />
-            Add Server Manually
+            Add Custom Server
           </button>
         )}
       </div>

tests/e2e/pages/ServersPage.ts

@@ -15,7 +15,7 @@ export class ServersPage extends BasePage {
   constructor(page: Page) {
     super(page);
     this.heading = page.getByRole('heading', { name: 'My Servers' });
-    this.addServerButton = page.getByRole('button', { name: /Add Server Manually/i });
+    this.addServerButton = page.getByRole('button', { name: /Add Custom Server/i });
     this.gatewayStatus = page.locator('text=Gateway Running, text=Gateway Stopped').first();
     this.startGatewayButton = page.getByRole('button', { name: 'Start Gateway' });
     this.serverList = page.locator('.space-y-3');