chore: rename project from podpuddle to podsteadr

Renames the repo directory and every podpuddle/PODPUDDLE reference
across code, config, and docs to podsteadr/PODSTEADR (package names,
Docker Compose project/service/volume names, env var names, UI/RSS
strings). Existing Docker volume data (uploaded blobs, mediamtx
recordings, the server's sqlite DB and its nostr identity key) was
migrated to new podsteadr_-prefixed volumes with matching filenames
so it isn't orphaned by the rename.

server/src/app.test.ts

@@ -29,7 +29,7 @@ function nip98Header(url: string, method: string): string {
 }
 
 beforeAll(async () => {
-  dataDir = mkdtempSync(join(tmpdir(), 'podpuddle-test-'));
+  dataDir = mkdtempSync(join(tmpdir(), 'podsteadr-test-'));
   const config = loadConfig({
     DATA_DIR: dataDir,
     PUBLIC_URL: 'http://localhost:8095',
@@ -59,7 +59,7 @@ describe('auth', () => {
     expect(res.json().pubkey).toBe(pk);
     expect(res.json().isAdmin).toBe(true); // first login claims admin
     const setCookie = res.headers['set-cookie'] as string;
-    expect(setCookie).toContain('podpuddle_session=');
+    expect(setCookie).toContain('podsteadr_session=');
     cookie = setCookie.split(';')[0];
   });
 
@@ -168,7 +168,7 @@ describe('streams + mediamtx auth webhook', () => {
       method: 'POST',
       url: '/api/streams',
       headers: { cookie },
-      payload: { title: 'Live Test', summary: 'hi', hashtags: ['podpuddle'] },
+      payload: { title: 'Live Test', summary: 'hi', hashtags: ['podsteadr'] },
     });
     expect(res.statusCode).toBe(201);
     const body = res.json();