fix(ci): systematic fixes for E2E tests and CI environment

- `js/nostr/client.js`: Exposed `derivePrivateKeyFromSecret` to `NostrClient` (delegating to `SignerManager`) to support programmatic login in E2E tests.
- `tests/e2e/helpers/bitvidTestFixture.ts`: Refactored to use dynamic relay ports based on `workerIndex` to fix parallel execution collisions.
- `scripts/agent/simple-relay.mjs`: Updated `close()` to force terminate connected clients, preventing test teardown hangs.
- `scripts/check-sw-compat.mjs`: Added try-catch around git commands to gracefully handle shallow clones in CI environments.

Co-authored-by: PR0M3TH3AN <[email protected]>

js/nostr/client.js

@@ -2417,6 +2417,10 @@ export class NostrClient {
     return this.signerManager.ensureActiveSignerForPubkey(pubkey);
   }
 
+  async derivePrivateKeyFromSecret(secret) {
+    return this.signerManager.derivePrivateKeyFromSecret(secret);
+  }
+
   async loginWithExtension(options) {
     // Check if ensureExtensionPermissions was overridden on this instance (e.g. by tests).
     // Only proxy when the own property differs from the prototype method to avoid recursion.