Move tavolo-app under packages/ for a uniform monorepo layout

Relocate the composition root (app, config, static, logging_config,
aerich_config) from server/src/tavolo/ to
packages/tavolo-app/src/tavolo/, with its own pyproject.toml and README
like the sibling distributions. Module paths and the granian entrypoint
are unchanged.

server/pyproject.toml remains as a tooling shim ([tool.aerich] next to
./migrations, [tool.mypy] for runs from server/); the Dockerfile installs
all three distributions from ./packages. Verified: all suites green,
mypy clean per package, aerich resolves the moved config identically,
wheel builds.

server/README.md

@@ -13,7 +13,7 @@ and [`packages/tavolo-scopone/README.md`](packages/tavolo-scopone/README.md)):
 - **`tavolo-scopone`** (`packages/tavolo-scopone/`) — scopone
   scientifico, the four-player, fixed-partnership variant of the classic
   Italian card game: pure rules plus the platform adapter.
-- **`tavolo-app`** (`src/tavolo/`, this `pyproject.toml`) — the
+- **`tavolo-app`** (`packages/tavolo-app/`) — the
   composition root wiring the platform to the scopone game, with the
   environment-driven settings and the SPA shell.
 
@@ -279,18 +279,15 @@ must dismiss. A play attempted in this phase is rejected with an
 ```sh
 python3 -m venv .venv
 .venv/bin/pip install -r requirements.txt
-.venv/bin/pip install -e ./packages/tavolo-platform -e ./packages/tavolo-scopone -e '.[dev]'
+.venv/bin/pip install -e ./packages/tavolo-platform -e ./packages/tavolo-scopone -e './packages/tavolo-app[dev]'
 # app integration suite:
 .venv/bin/python -m unittest discover -s tests -t .
 # per-package suites (each package is self-contained):
 .venv/bin/python -m unittest discover -s packages/tavolo-platform/tests
 .venv/bin/python -m unittest discover -s packages/tavolo-scopone/tests
-# type checks:
+# type checks (see packages/tavolo-app/README.md for the app modules):
 .venv/bin/python -m mypy -p tavolo.platform
 .venv/bin/python -m mypy -p tavolo.scopone
-.venv/bin/python -m mypy --namespace-packages --explicit-package-bases \
-  src/tavolo/app.py src/tavolo/config.py src/tavolo/static.py \
-  src/tavolo/aerich_config.py src/tavolo/logging_config.py
 ```
 
 Tests run fully in-process: in-memory sqlite for Postgres, in-memory stores
@@ -348,12 +345,14 @@ packages/tavolo-scopone/      # scopone scientifico game (own pyproject + tests)
   ├── engine.py               # pure scopone scientifico rules
   ├── errors.py               # scopone-specific rule violations
   └── plugin.py               # ScoponeEngine: the GameEngine adapter
-src/tavolo/                   # tavolo-app: composition root (this pyproject.toml)
-├── app.py                    # session/OIDC/Tortoise/OpenAPI/Platform/DeadlineScheduler mixins
-├── config.py                 # env -> frozen Settings
-├── aerich_config.py          # aerich CLI configuration
-├── logging_config.py         # logging setup
-└── static.py                 # SPA shell hosting
+packages/tavolo-app/          # deployable app: composition root (own pyproject)
+  src/tavolo/
+  ├── app.py                  # session/OIDC/Tortoise/OpenAPI/Platform/DeadlineScheduler mixins
+  ├── config.py               # env -> frozen Settings
+  ├── aerich_config.py        # aerich CLI configuration
+  ├── logging_config.py       # logging setup
+  └── static.py               # SPA shell hosting
+pyproject.toml                # tooling shim: [tool.aerich] + [tool.mypy] for server/ CWD
 migrations/                   # aerich migrations for the platform models
 tests/                        # app integration suite (platform + scopone wired together)
 ```