docs: move the engineering documents into docs/

Thirteen files at the repository root, seven of them documents. Only README.md
earns a place there; the rest are now in docs/ beside the meeting notes, the
client roadmap and the historical material.

The compose files stay. docker-compose.yml is the path the dtf-cloud Portainer
stack reads, so moving it would break deployment, and Docker resolves a compose
file's relative build contexts against its own directory, so moving the other
two would silently break every build. Both reasons are now written down where
someone would otherwise try it.

Correcting references turned up a live fault: the Portainer stack creation
instructions still named deploy/stack.yaml as the compose path. That file was
removed, so anyone recreating the stack from these instructions would have
failed. It names docker-compose.yml now, with the reason it stays at the root.

ROADMAP.md keeps the paths its closed findings were written with, and says so at
the top. Those entries record where a fault was when it was found; rewriting
them to match a later layout would make the record less true, not more.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

README.md

@@ -1,12 +1,12 @@
 # Sistema DTF 24h — Altus Group
 
-> **Active local milestone (2026-09-11):** Read [CONTEXT.md](CONTEXT.md) first.
+> **Active local milestone (2026-09-11):** Read [docs/CONTEXT.md](docs/CONTEXT.md) first.
 > Start with `docker compose up --build`, then open the [Site](http://localhost:8080)
 > and [Kanban](http://localhost:8081). Optional configuration: copy `.env.example`
-> to `.env`. Follow [LOCAL_SETUP.md](LOCAL_SETUP.md) for the complete test flow,
+> to `.env`. Follow [docs/LOCAL_SETUP.md](docs/LOCAL_SETUP.md) for the complete test flow,
 > local login, health checks, and troubleshooting. See
-> [IMPLEMENTATION_REPORT.md](IMPLEMENTATION_REPORT.md) for scope and reuse decisions.
-> Production delivery uses one Portainer stack; see [PORTAINER.md](PORTAINER.md).
+> [IMPLEMENTATION_REPORT.md](docs/historico/IMPLEMENTATION_REPORT.md) for scope and reuse decisions.
+> Production delivery uses one Portainer stack; see [docs/PORTAINER.md](docs/PORTAINER.md).
 > Everything below is preserved historical prototype documentation, not the active
 > setup or delivery specification. Do not run its production integrations or agent.
 
@@ -20,8 +20,8 @@
 > `schema.sql`, `.env.exemplo`) no longer exists, and the model it describes is
 > not the one implemented. Kept for the business reasoning in it — the capacity
 > figures, the cost argument, the meeting decisions. For how the system actually
-> works read [CONTEXT.md](CONTEXT.md); for what is outstanding read
-> [ROADMAP.md](ROADMAP.md); for the original documents see
+> works read [docs/CONTEXT.md](docs/CONTEXT.md); for what is outstanding read
+> [docs/ROADMAP.md](docs/ROADMAP.md); for the original documents see
 > [docs/historico/](docs/historico/README.md).
 
 ---