Prove the M101 dose-model switch; record the judged dose curves

The stream harness gains rules 18 to 21: the floor is derived from the
selected model's config key at the arm and a typed $35 is overwritten;
M101 switches the rendering exactly at the boundary in both directions
with no continuous FIRE at full duty across it; a refused switch (the
spindle on) leaves the stream unchanged, and the harness resyncs with
an empty line because the core skips G-code after an error until the
sender resyncs; M2 reverts a program-scoped switch and Q1 holds. The
analog sessions pin laser_floor_analog at the density floor so the
existing duty expectations stand, and the density ladder's unfloored
run moves from a chained $35 write to the laser_floor_density key.

The catalog's laser.power-floor becomes model-aware: it reads the
configured model and the floor keys from forgectrl, switches to the
configured model with M101 so the derivation runs without a fire, and
expects $35 to be that model's floor. The new laser.power-model-switch
switches to each model with the spindle off, checks the reported
message and $35 after each switch, and checks the M2 revert. The new
mswitch bench drill runs the switch on the machine in one armed run.

Docs follow: BRINGUP's Laser control section describes the switch, the
derived floors and the measured dose response of both models; the
MOTION settings table gains the five keys; LIGHTBURN gains a Power
models section and drops the stale 30 percent floor advice; SAFETY
names the switch's refusal rule; the CAMPAIGN-LOG records the judged
depth-witness runs of 2026-08-30 and the switch's host and bench proof.

docs/CAMPAIGN-LOG.md

@@ -5986,6 +5986,20 @@ Closed: the arm is decided by the window alone (grblHAL-glowforge a7dcdca), an R
     `serial.c`.
 
 
+### The dose curves judged on material, and the model switch built, 2026-08-30
+
+Bench, dev image 20260829220329, three `dpatch` depth-witness runs, each two rows of 30 x 4 mm serpentine fills (row A CW at six feeds for relative doses 1.0 to 0.25, row B at the reference feed at 100 / 80 / 60 / 45 / 30 % of the model's range), the operator matching each row-B patch to the row-A patch of equal depth by eye:
+
+- Density on Thick Draftboard at F1500 (`bench-data/dpatch_20260830-172227.json`) and on acrylic at F1125 (`dpatch_20260830-173933.json`): the operator's verdict on both, "sensor predictions are accurate", B8 (80 % density) = A4 (CW at half the dose), B9 = A5, B10 = A6, B7 = A1. Thermopile 0.47 / 0.35 / 0.19 / 0.07 of CW at 80 / 60 / 45 / 30 % (0.45 / 0.34 / 0.19 / 0.06 on acrylic), tube current 0.56 / 0.45 / 0.39 / 0.35. Row A flat within 17 % and 16 %. The density curve is the tube's, not the sensor's, and the pending question from 2026-08-25 (B8 = A4 or A2) is closed on A4. By eye: every box deeper at both ends (the reversal slow-down under constant power), a slight line pattern from the 0.3 mm serpentine, no dot pattern.
+- Analog on acrylic at F1125 (`dpatch_20260830-175759.json`), the drill extended to run under `laser_power_model = analog` (forgefirm f88c778): "they match the sensors", B8 (80 % duty) = A2, B9 between A2 and A3, B10 = A4, B11 = A5; light 0.82 / 0.68 / 0.54 / 0.37 of CW at 80 / 60 / 45 / 30 % duty, current 0.80 / 0.61 / 0.46 / 0.31. The 2026-08-25 ladder's prior (0.72 / 0.52 / 0.37 / 0.07) was low, worst at 30 % duty where its F600 lines sat in the unstable discharge band. The thermopile drifted inside this run (row A 1733 down to 1290, baseline 1835 up to 1896), so the ratios carry more uncertainty than the density runs.
+- Finish, the two acrylic runs side by side: "finish is the same"; the only visible pattern is present at every power, under CW and under 100 % density (continuous fire) alike, so it is mechanical, not the dither. Operator's decision: the analog model stays and is developed as a second, near-linear model.
+
+Each run: `cool_flow_recheck_s = 600` for the run and removed after, the `dpatch` record copied to the tree, `/tmp` cleaned, `laser_power_model` put back to `density`, the machine idle and disarmed.
+
+Built the same day, host-proven, no fire: the dose-model switch. `M101 P0` (analog) / `M101 P1` (density) as a driver M-code, refused with the spindle commanded on (error 253, reason reported) or the controller not idle, program-scoped with `Q1` to stick; the per-model floors as config keys (`laser_floor_density` 10, `laser_floor_analog` 16) loaded into `$35` in RAM at every arm and switch with the PWM mapping re-precomputed, the stored setting never written; the stream leading the first run after a switch dark; the cooling report carrying the model in force (`model=` on `POST /cool/state`, the engine preferring it to the config key for the tube-heat share); the five `laser_*` keys in forgectrl's settings whitelist and the panel's GRBL tab with help text; `laser.power-floor` made model-aware and the new catalog test `laser.power-model-switch`. Proof: `tests/laser_arm_test.c` cases J to O (derived floors, validate and execute refusals, switch, revert, Q1, reset), `laser_stream_test.py` rules 18 to 21 (a typed `$35` overwritten at the arm; both switch directions rendering exactly at the boundary with no continuous FIRE at full duty across it; the refusal leaving the stream unchanged; `M2` reverting and `Q1` holding), forgectrl's host tests. Found on the way: the core skips every G-code line after an error until the sender resyncs with an empty line or a `$` command (`protocol.c`), which is how the harness now follows a refused switch. One flake, not a defect: rule 13's mask comparison slipped one tick at the tail while a build ran alongside in the same VM (the shipper is wall-paced); three runs alone were identical.
+
+Bench-proven the same day, one armed run of the new `mswitch` drill on the hot-installed cross-built binaries (forgectrl md5 4dc4677a, grblHAL_glowforge 17e5502f, operator-run install): the arm reported "laser armed (density, floor 10 %)", `M5` then `M101 P0` answered ok and reported "laser power model set for this program (analog, floor 16 %)", `$$` read `$35=16` while analog was in force and `$35=10` again after `M2` reported the revert, the armed window carried across the switch with no re-prompt, and the 25 Hz trace showed exactly two discharge segments, the density line pulsed (hv mean 390, max-mean 547) and the analog line steady (mean 567, max-mean 28), dark after the second `M5` (hv max 0). Board cleaned; the hot-deployed binaries stay until the next flash, `/tmp/*.prev` is the rollback.
+
 ## Reference notes
 
 ### Head-IRQ source validation — the beam-emission hypothesis