SAFETY-04 review fixes: the freeze deadlocked, the bound was too loose

S-1. The frozen branch admitted a correction only if it shrank |i_w|. That is
unsatisfiable for BOTH signs of error whenever |correction| > 2*|i_w|, i.e.
whenever the integrator is near zero, so the loop stopped moving and the freeze
could never clear - it clears when the inverter tracks, and not tracking is
what saturation means. Measured: 0 W held into a 2 kW import indefinitely,
where release/1.0 recovers on the next cycle. Re-encoded as the same asymmetric
rule the output freeze has always used: may not wind further in the direction
it is already pushing, may fall, cross zero or reverse. Same interpretation,
an encoding that cannot deadlock.

S-2. integrator_max_w defaulted to 1.5x max_w, which ADDED windup: in
release/1.0 the accumulator was the post-clamp command and could never pass the
rail. Default is now "follow max_w" (config 0 = unset). Measured on the 4000 W
load-drop sim, first cycle after the drop: 1000 W at the new default, 1800 W at
3000. DOCS row inverted - the useful direction is below max_w, and the 14 768 W
anecdote is a vendor controller, not evidence about this code.

S-3. The claim that i_w=None preserved release/1.0 exactly was false, because
the S-1 gate ran regardless of seeding. It is true again, and now asserted
rather than asserted-about: 3024-case exhaustive comparison against a
transcription of the old law, over both freeze states, both signs and either
side of the deadband. Added the carried-i_w convergence/overshoot sim that the
shipped configuration was missing.

S-4. Cycles are distinct meter values, not seconds: cycle() runs only when the
meter reading changes, so the window has no wall-clock bound. Comment and DOCS
corrected; the stall is detection latency, not a windup hazard, because the
same condition stalls the whole loop.

test_control.py: 33 -> 41 checks, all passing.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Du77usMj8XNKNFZGmUiWDa

goodwe_controller/config.yaml

@@ -48,7 +48,7 @@ options:
   step_w: 10
   saturation_w: 500
   saturation_cycles: 3
-  integrator_max_w: 3000
+  integrator_max_w: 0
   heartbeat_s: 10
   stale_input_s: 15
   auto_start: false
@@ -89,7 +89,7 @@ schema:
   step_w: int(1,100)
   saturation_w: int(100,2000)
   saturation_cycles: int(1,10)
-  integrator_max_w: int(100,15000)
+  integrator_max_w: int(0,15000)
   heartbeat_s: int(2,25)
   stale_input_s: int(5,120)
   auto_start: bool