feat(desktop): use healthchat:// deep-link scheme instead of element://

Switch the friendly deep-link / legacy SSO callback scheme from element://
to healthchat:// and stop registering element:// entirely. The reverse-DNS
OIDC primary scheme (ch.healthchat.desktop://) is unchanged. Also rebrand the
round-tripped SSO id param element-desktop-ssoid -> healthchat-desktop-ssoid
on both the desktop and web sides.

apps/web/src/BasePlatform.ts

@@ -456,7 +456,7 @@ export default abstract class BasePlatform {
 
     /**
      * Suffix to append to the `state` parameter of OIDC /auth calls. Will be round-tripped to the callback URI.
-     * Currently only required for ElectronPlatform for passing element-desktop-ssoid.
+     * Currently only required for ElectronPlatform for passing healthchat-desktop-ssoid.
      */
     public getOidcClientState(): string {
         return "";

apps/web/src/vector/platform/ElectronPlatform.tsx

@@ -53,7 +53,7 @@ interface SquirrelUpdate {
     updateURL: string;
 }
 
-const SSO_ID_KEY = "element-desktop-ssoid";
+const SSO_ID_KEY = "healthchat-desktop-ssoid";
 
 function platformFriendlyName(): string {
     // used to use window.process but the same info is available here
@@ -466,7 +466,7 @@ export default class ElectronPlatform extends BasePlatform {
 
     public getSSOCallbackUrl(fragmentAfterLogin?: string): URL {
         const url = super.getSSOCallbackUrl(fragmentAfterLogin);
-        url.protocol = "element";
+        url.protocol = "healthchat";
         url.searchParams.set(SSO_ID_KEY, this.sessionId);
         return url;
     }

apps/web/test/unit-tests/vector/platform/ElectronPlatform-test.ts

@@ -83,7 +83,7 @@ describe("ElectronPlatform", () => {
     it("should return oidc client state as expected", async () => {
         const platform = new ElectronPlatform();
         await platform.getConfig();
-        expect(platform.getOidcClientState()).toMatchInlineSnapshot(`":element-desktop-ssoid:session-id"`);
+        expect(platform.getOidcClientState()).toMatchInlineSnapshot(`":healthchat-desktop-ssoid:session-id"`);
     });
 
     it("dispatches view settings action on preferences event", () => {