docs: generate gitea wiki pages + publish script

add wiki/ markdown pages (Home, Sidebar, architecture, transport, developer, usage)

add scripts/publish_gitea_wiki.sh to sync wiki repo

fix: serialize aggregate env-setting tests to avoid parallel env var races

wiki/NATS-Reference.md

@@ -0,0 +1,17 @@
+# NATS Reference
+
+## Subjects
+- Aggregate events: tenant.<tenant>.aggregate.<type>.<id>
+- Workflow commands/events: shared helpers define exact formats
+
+## Headers (Producers)
+- tenant-id: required
+- Nats-Msg-Id: idempotency key (event_id, command_id, etc.)
+- x-correlation-id and correlation-id
+- traceparent and trace-id
+
+## Consumers
+- AckPolicy::Explicit
+- ack_wait: bounded timeout
+- max_deliver: bounded
+- max_ack_pending: aligned with concurrency