MAINT-21: tests read and patch the Controller through tools/main_files.py

Prepares the split of app/main.py's Controller into files by job, with no app
change. tools/main_files.py gives a test the text and the AST of main.py plus
the files split from it, and `live`, which sets a global in every file whose
functions read it (and raises when none does). Tests that read main.py's
source, and tests and replay tools that patch a main global (datetime,
compute, resolve, _mono, WRITE_BUDGET_S, ...), go through it, so they pass on
this layout and on the split one. test_split_patches.py fails when a test or
tool patches an app.main attribute that main.py no longer reads, or that
another file also reads. tools/maint21_same_ast.py proves every function,
method and module-level assignment of main.py at the base is found unchanged
in its new file.

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

goodwe_controller/test_static_tariff.py

@@ -81,6 +81,8 @@ from app.static_tariff import (
 from app.validate import validate_startup_config
 
 HERE = Path(__file__).resolve().parent
+sys.path.insert(0, str(HERE / "tools"))
+import main_files  # noqa: E402
 UTC = timezone.utc
 
 # PRICE-02: `TariffPlan.arbitrage(now=...)` is required. This instant is before every
@@ -893,7 +895,7 @@ check("the new module holds no option-defaults dict of its own, so this ticket "
 check("...and it reads the option through price.price_option(), the framework's "
       "single read path, rather than through opts.get(key, <a number>)",
       "price_option(opts" in _SRC and 'opts.get("static_profile"' not in _SRC)
-_MAIN = (HERE / "app" / "main.py").read_text(encoding="utf-8")
+_MAIN = main_files.source()
 check("...and main.py grew no `o.get(\"static_profile\", <a default>)` fallback "
       "either - it calls static_status(o, now), and the option is read once, "
       "inside the framework",