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/Architecture-Overview.md

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+# Architecture Overview
+
+## Monorepo
+- Rust workspace: aggregate, projection, runner, gateway, control/api, shared
+- Frontend: control/ui
+- Infra: docker, observability, swarm
+
+## Data Flow
+- Clients → Gateway (HTTP/JSON)
+- Gateway ↔ Nodes (gRPC)
+- Nodes ↔ NATS (JetStream + KV)
+
+## Services
+- Aggregate: command handling + event sourcing; publishes events to JetStream
+- Projection: materialized views; consumes aggregate events; exposes QueryService (gRPC)
+- Runner: workflow/saga engine + effects/outbox; exposes RunnerAdmin (gRPC)
+- Gateway: edge, authn/z, routing to nodes, admin entry points
+
+## Observability
+- /health, /ready, /metrics on all services
+- Correlation and tracing propagated across HTTP, gRPC, and NATS