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/Quick-Start.md

@@ -0,0 +1,19 @@
+# Quick Start
+
+## Compose
+```bash
+docker compose up -d --build
+```
+
+Full stack with observability:
+```bash
+docker compose -f docker-compose.yml -f observability/docker-compose.yml up -d --build
+```
+
+## Local Dev (minimal)
+```bash
+cargo run -p aggregate
+cargo run -p projection
+cargo run -p runner
+cargo run -p gateway
+```