docs: the moved documents live on the documentation site

INSTALL.md, SERIAL.md, docs/COOLING.md, docs/LIGHTBURN.md,
docs/MOTION.md, docs/SAFETY.md, docs/UPDATE-SYSTEM.md, docs/VIDEO.md and
their images are pages on https://docs.forgefirm.org/ now. Every
reference in the README, BRINGUP, the kas config, the cold-build
workflow, forgetest, and the bench scripts points to the site page. The
README carries the beta banner. docs/ keeps BRINGUP.md and
CAMPAIGN-LOG.md.

No catalog consequence: the deleted files are documents, and the code
changes are comment and help-text repoints only.

forgetest/forgetest/bench.py

@@ -189,8 +189,8 @@ TOOLS = [
                    ["watch", "point", "fit", "supply-watch", "supply-point", "supply-fit"]),
               _arg("value", "str", None, "point: the thermometer reading in C; watch: seconds (default 60)")],
      "desc": "Pairs a measured temperature with averaged raw readings; fits a per-machine line. The coolant "
-             "sensors, or the power supply's (thermometer on its heatsink, against the unverified guess in "
-             "UAPI.md). Points accumulate in the bench data directory."},
+             "sensors, or the power supply's (thermometer on its heatsink, against the documented unverified "
+             "guess). Points accumulate in the bench data directory."},
     {"id": "fan-test", "title": "Fan/coolant bench", "script": "fan_test.py",
      "safety": "dry", "where": "board", "ported": True, "args": [],
      "desc": "Snapshots fan PWMs/tachs/temps, drives M8 -> cut fans, M9 -> cooldown -> idle; the tach "

forgetest/forgetest/suite/kernel.py

@@ -27,7 +27,7 @@ from ..catalog import test
 from .. import hw
 from ..runner import Failed
 
-# interlock_circuit bits (UAPI.md): bit 3 = the driven latch line, set = locked.
+# interlock_circuit bits (docs.forgefirm.org, the kernel module page): bit 3 = the driven latch line, set = locked.
 LATCH_BIT = 1 << 3
 
 TICK_HZ = 10000