refactor: rename ws adapter to server across codebase

'ws' conflated storage mode with transport protocol (WebSocket). Renamed for
clarity: the adapter talks the self-hosted server (src/storage/server.js), which
happens to use WebSocket for realtime — but the name should describe what it
connects to, not how.

Renames:
- src/storage/ws.js -> server.js
- createWsStorage() -> createServerStorage()
- storage mode 'ws' -> 'server'
- REACT_APP_BACKEND_WS -> REACT_APP_BACKEND_REALTIME_URL
- factory param wsUrl -> realtimeUrl
- server/tests/ws-*.test.js -> server-*.test.js

Kept literal: 'ws' npm package, ws:// protocol URLs, /ws WebSocket endpoint.
Transport is accurate there; only storage-naming changed.

Updated all docs (DEVELOPMENT, TESTING, REWORK_PLAN, GLOSSARY, TODO), scripts
(dev-start.sh, replay-combat.js), factory + ESM tests. 204 tests green.

src/tests/StorageEsm.test.js

@@ -1,6 +1,6 @@
 // Lock: storage adapters must use ESM exports (no module.exports).
 // Regression guard: CJS in src/ crashes CRA prod build (ESM strict).
-// Bug history: ws.js + firebase.js used module.exports. Dev lenient (masked),
+// Bug history: server.js + firebase.js used module.exports. Dev lenient (masked),
 // prod bundle crashed blank page. firebase.js always ESM.
 import fs from 'fs';
 import path from 'path';
@@ -8,7 +8,7 @@ import path from 'path';
 const ADAPTER_DIR = path.join(__dirname, '..', 'storage');
 
 describe('storage adapters use ESM (no CJS)', () => {
-  const adapters = ['ws.js', 'firebase.js', 'index.js'];
+  const adapters = ['server.js', 'firebase.js', 'index.js'];
   test.each(adapters)('%s has no module.exports', (file) => {
     const full = fs.readFileSync(path.join(ADAPTER_DIR, file), 'utf8');
     // strip line comments so words like 'require' in explanatory comments don't trip the guard