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_opt27.py

@@ -46,6 +46,7 @@ logging.disable(logging.WARNING)
 
 import opt11p3_replay as rp                                    # noqa: E402
 from named_absence import first, nth, present                  # noqa: E402
+import main_files  # noqa: E402
 import app.main as m                                           # noqa: E402
 from app import homeview, modetrade, solarfc                   # noqa: E402
 from app.main import Controller                                # noqa: E402
@@ -404,14 +405,14 @@ def drive27(o, sensors, *, pre, start, minutes=20, restart=None,
 
     async def go():
         c, hass = build(store)
-        real_dt, real_hv = m.datetime, homeview.datetime
+        real_dt, real_hv = main_files.live.datetime, homeview.datetime
 
         class _DT(real_dt):
             @classmethod
             def now(cls, tz=None):
                 return clock[0] if tz is None else clock[0].astimezone(tz)
 
-        m.datetime = homeview.datetime = _DT
+        main_files.live.datetime = homeview.datetime = _DT
         task = None
         try:
             for t_pre in pre:
@@ -477,7 +478,7 @@ def drive27(o, sensors, *, pre, start, minutes=20, restart=None,
                     await task
                 except asyncio.CancelledError:
                     pass
-            m.datetime, homeview.datetime = real_dt, real_hv
+            main_files.live.datetime, homeview.datetime = real_dt, real_hv
         return c
 
     return asyncio.run(go()), rows, pre_rows