docs: reorganize operational documentation

docs/architecture/overview.md

@@ -22,7 +22,7 @@ flowchart LR
     THT --> FE
 ```
 
-## The three independent projects
+## The three independently built layers
 
 ```
 frontend (React/SSE) → backend (Fastify) → pi --mode rpc → tht/harness → DWH (read-only)
@@ -100,8 +100,13 @@ operations that perform this upgrade.
 - Settings are global (`backend/data/settings.json`: workspace/provider/model/thinking); the new-session form asks only for the question.
 - **Resume**: a resumable session returns to its last incomplete phase. The backend rejects resume with 409 when `finalized` or `archived`; `PiProcessManager.spawnFor` must send `/riprendi-sessione <id>` for resume and `/nuova-domanda` for a new session. The wrong prompt silently turns a resume into a new question.
 
-## Starting the stack
+## Runtime composition
 
-Start the local stack with `./scripts/run-stack.sh` after creating
-`deploy/env/local.env` from `deploy/env/local.env.example`. The Compose core includes Pi; DWH,
-the vector database, embeddings, and the LLM are external endpoints configured in the local file.
+The local stack is started by `./scripts/run-stack.sh` after the installation descriptor and
+`deploy/env/local.env` exist. `core` includes Pi. `catalog-db`, Qdrant, and the Ollama embedding
+service are internal Compose services; only the DWH and model-provider endpoint remain external.
+The launcher runs the explicit `catalog-migrate` one-shot service before application startup.
+
+For the operator sequence, see [Install and first start](../install/first-start.md). For the
+two user-facing paths, see [User guide](../guida-utente.md) and
+[Database management](../operations/database-management.md).