MAINT-21: comments only - trim restated notes, add DECISIONS pointers

No code change: tools/maint21_same_ast.py and tools/maint20_same_code.py HEAD~
both print OK, and the -OO code objects are the same.

- Trims 56 comment and docstring lines (2088 -> 2032) in app/main.py and the
  new files that only restated their MAIN-orchestration.md bullet, each cut to
  its first sentence and a pointer. What the cut comments said and the bullet
  did not is now in the bullet: why a SAFETY-02 latch is restored, why the
  SAFETY-30 site check is not armed at one inverter, the SAFETY-18 re-derive,
  the MAINT-05 one-config rule, the OPT-09 sizing rules, the "no plan" row,
  the 5 400 s age bound, and the guard being the only latch repair.
- Adds the missing DECISIONS pointers on the SMA-10, SAFETY-137 and SMA-2
  comments (FALLBACK_BUDGET_S, write_setpoint, _await_inflight,
  _release_last, the retry wait, the failed-release branch, release_zero_sent,
  the in-flight write, the stop_event hand-back, the SMA-2 read and driver).
- DECISIONS/SAFETY-32: the stale `main.py:932-936` now names
  Controller.pack_floor_soc.
- main.py's docstring and import block say where the Controller's parts are.

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

goodwe_controller/app/ctl_trade.py

@@ -82,14 +82,10 @@ MAINT_CHARGING_W = 50.0
 
 class TradeMixin:
     def trade_power_w(self, floor_pct, ceiling_pct) -> tuple:
-        """OPT-09. `(charge_w, discharge_w)`: how hard a trade may be SIZED:
-        what the site can push AND STILL HAVE SOMEWHERE TO PUT. The bounds are
-        arbitrage's own (`arbitrage_soc_floor` / `_ceiling`), NOT the BMS
-        cut-out that `packshare.envelope()` uses (SAFETY-25): different
-        questions. It sizes the ask, it does not route it. A pack whose SoC did
-        not read counts on neither side. Neither side may be zero on a trading
-        tick (`arbitrage.decide()` refuses `IDLE_NO_SIZE`: a 0 W claim is a
-        park order). DECISIONS/MAIN-orchestration.md."""
+        """OPT-09. `(charge_w, discharge_w)`: how hard a trade may be SIZED,
+        on arbitrage's own SoC bounds, not the BMS cut-out. A pack whose SoC
+        did not read counts on neither side; neither side may be zero on a
+        trading tick (`IDLE_NO_SIZE`). DECISIONS/MAIN-orchestration.md."""
         # The reduction lives in `packshare`; `test_packshare.py` part 9 calls
         # the SAME function (a transcription in a check is a copy that drifts).
         return packshare.trade_power_w(self.pack_energy, floor_pct, ceiling_pct)