feat(local): model local command log boundary

Define local/offline truth as commands, domain events, and projections rather than stored DOM patches or EffectBatch payloads, and wire the techdemo through a local command-to-projection-to-effect flow.

req: local/001

req: local/002

req: local/003

req: local/004

req: examples/001

README.md

@@ -91,7 +91,9 @@ and integrate at explicit boundaries. req: laws/002 req: auth/001
   vendor providers or add framework-specific magic. See `docs/recipes/observability-flags.md` and `docs/recipes/deploy-versioning.md`.
 - **PWA/offline/sync:** optional adapters may reuse generated targets/effects,
   but core hemx must not gain a mandatory client state graph or local app
-  runtime. See `docs/recipes/pwa-offline.md`. req: canonical_authoring/008
+  runtime. Local truth is commands/events/projections, not stored DOM patches or
+  stored `EffectBatch` payloads. See `docs/recipes/pwa-offline.md` and
+  `docs/recipes/local-command-log.md`. req: canonical_authoring/008 req: local/001 req: local/002
 - **Host capabilities:** browser, PWA, WebView, and native-shell capabilities use
   `hemx-host` manifests/calls/events. Adapters return host facts to app code;
   UI still changes through normal hemx effects. See