[feat] setup master from fork with fastapi + otel

docs/005-fastapi-otel-early-instrumentation.md

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+# 005 Early FastAPI OTel Instrumentation
+
+Context
+- HTTP spans and HTTP metrics are provided by FastAPI/ASGI OpenTelemetry middleware.
+- Starlette caches `middleware_stack` on first ASGI entry, including lifespan startup.
+- Instrumenting FastAPI inside lifespan is too late for the initial middleware stack.
+
+Decision
+- Build the application container before returning the FastAPI app from `create_app`.
+- Configure FastAPI OpenTelemetry instrumentation in the app factory, not in lifespan.
+- Pass the configured tracer and meter providers directly to `FastAPIInstrumentor.instrument_app(...)`.
+- Keep lifespan focused on shutdown and resource cleanup.
+
+Consequences
+- `OpenTelemetryMiddleware` is present in the runtime stack without manual stack rebuilds.
+- HTTP traces and HTTP metrics use the same startup wiring as other singleton adapters.
+- Observability bootstrap stays explicit in the outer adapter layer.