Adopts the layout feedback landed in cb49dd67: secondary adapters live
under `app/adapters/<context>/`, one file per port, the file named after
the port in snake_case with the technology carried by the class name.
`app/infra/` is now gone entirely.
The rename also separates two meanings of "run" that shared one filename
space: `run_sql.py` held `ScheduledRun` (an execution record), while the
`run_launcher.py` still to come deals in Gateway runs.
task_sql.py -> scheduled_task_repository.py
run_sql.py -> scheduled_run_repository.py
spec_mapping.py -> spec_mapping.py (implements no port, so no rename)
Both SQL adapters now carry the `Secondary adapter (owned persistence)`
docstring marker -- this context owns both tables and writes its own
queries. `spec_mapping` says instead that it is a boundary mapping and
names its two callers. The package `__init__.py` is empty, so imports go
through the full path and a class's home file stays unambiguous.
Pure move: every top-level symbol was compared against its pre-move
original by AST dump (docstrings excluded), plus a separate per-class
method-name comparison, since a whole-class dump reports a docstring edit
and a renamed method the same way.
Also repoints three docstrings and one diagram that still named the
deleted `app/infra/` path.
Hexagonal inner ring for the feedback bounded context: frozen aggregate
with construct-time invariants (rating, reason-tag slugs), technology-
neutral ports (typing.Protocol), and the application service with
explicit user_id. Guarded by an AST purity test that keeps domain/ free
of infrastructure imports.
