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/requirements.txt

@@ -4,11 +4,12 @@
 #
 #    pip-compile --allow-unsafe --extra-index-url=https://pypi.org/simple --index-url=https://gitea.woggioni.net/api/packages/woggioni/pypi/simple --output-file=requirements.txt pyproject.toml
 #
-# NOTE: the tavolo-platform and tavolo-scopone sibling packages are NOT
-# pinned here: they are installed from ./packages in the Dockerfile and in
-# development (pip install -e ./packages/* -e .). All of their third-party
-# dependencies are direct dependencies of tavolo-app, so this lock covers
-# the full closure.
+# NOTE: the tavolo-platform, tavolo-scopone and tavolo-app sibling packages
+# are NOT pinned here: they are installed from ./packages in the Dockerfile
+# and in development (pip install -e ./packages/tavolo-platform
+# -e ./packages/tavolo-scopone -e ./packages/tavolo-app). All of their
+# third-party dependencies are direct dependencies of tavolo-app, so this
+# lock covers the full closure.
 #
 --index-url https://gitea.woggioni.net/api/packages/woggioni/pypi/simple
 --extra-index-url https://pypi.org/simple