Prove the density-only model; record the rasters and the decision

The stream harness keeps the analog rendering as the host-test
conservatism reference (rule 13's mask, the duty ladders) and drops the
M101 switch sessions; rule 18 stays as the derived-floor proof, now
satisfied from boot by the precompute. The lifecycle harness's
state-files scenario asserts the derived floor is in $$ before any arm.
The catalog's laser.power-model-switch goes and laser.power-floor reads
the one floor key with no M-code needed. The mswitch drill goes; the
m4corner drill becomes a single density pass; the dpatch drill returns
to density only.

The CAMPAIGN-LOG records the first rasters (254 and 508 DPI grayscale
wedges: tonality held to ~14 pulse slots per pixel, no dither artifact,
one benign stale-verdict suppression under CPU starvation) and the
decision that ends the analog mode - the strike transient fires a spot
at every beam-on, and the finish comparison found no advantage. BRINGUP,
LIGHTBURN, MOTION and SAFETY describe the density-only present.

docs/BRINGUP.md

@@ -206,69 +206,48 @@ of the first tick byte it covers, FIRE as bit 4 OR'd into tick bytes. The
 spindle PWM is precomputed to a period of exactly 127, so computed values ARE
 power bytes (`$30` default 1000 → S1000 = 127).
 
-**Dose model.** Two models render the per-segment value the core computes:
-`density` (the default) pins the duty at full and modulates the FIRE bit,
-`analog` ships the value as a power byte instead. Density uses a base
-period of `laser_pulse_ticks` (default 20 = 710 us at 28160 Hz, the
-factory's ~1.43 kHz) whose on-count is dithered between adjacent integers
-with the remainder carried, so densities finer than one tick per period
-average out. Density is what the tube's dead band below its lasing
-threshold requires: every pulse it emits is full-power, so no commanded
-level lands in the band, and a level change inside a run costs no stream
-byte at all. `laser_pulse_min_ticks` (default 3 = 106 us) is the shortest
-pulse it will emit: below it a period is skipped and its debt carried, so a
-faint level arrives as fewer full-width pulses instead of stubs the supply
-cannot strike - measured on the bench, a 36 us stub draws no discharge at
-all, and the factory never emits below one of its 100 us ticks. The debt is
-conserved, so the average density is unchanged: at level 2 the stream goes
-from 444 one-tick bursts to 147 three-tick bursts, same density to four
-decimals. Structurally the model is a mask on the core's fire state and
-never a source of one, so emission stays exactly where the core commanded
-it.
+**Dose model: density, the only one.** The shipper renders the
+per-segment value the core computes by pinning the duty at full and
+modulating the FIRE bit on a base period of `laser_pulse_ticks` (default
+20 = 710 us at 28160 Hz, the factory's ~1.43 kHz) whose on-count is
+dithered between adjacent integers with the remainder carried, so
+densities finer than one tick per period average out. Every pulse is
+full-power, so no commanded level can land in the tube's dead band, and
+no beam-on ever dwells: the analog alternative (duty as the power byte,
+continuous FIRE) fires the strike transient as a visible spot at every
+turn-on whatever the power, and was removed as a product mode for it -
+the rendering survives only as the host harness's conservatism
+reference, selectable solely in the null-sink build.
+`laser_pulse_min_ticks` (default 3 = 106 us) is the shortest pulse the
+model emits: below it a period is skipped and its debt carried, so a
+faint level arrives as fewer full-width pulses instead of stubs the
+supply cannot strike - measured on the bench, a 36 us stub draws no
+discharge at all, and the factory never emits below one of its 100 us
+ticks. The debt is conserved, so the average density is unchanged: at
+level 2 the stream goes from 444 one-tick bursts to 147 three-tick
+bursts, same density to four decimals. Structurally the model is a mask
+on the core's fire state and never a source of one, so emission stays
+exactly where the core commanded it.
 
-**Selecting the model.** `laser_power_model` in the shared machine config
-(the control panel's GRBL tab) is the boot default. A job selects its own
-with the driver M-code `M101 P0` (analog) or `M101 P1` (density), sent with
-the spindle off: the switch is refused (`error:253`, reason reported) with
-the spindle commanded on or the controller not idle, because a model change
-under fire could pair density's pinned full duty with analog's continuous
-FIRE; between kernel runs, which end dark and lead with a power byte, there
-is no torn state to reach. The planner drains before the switch, the armed
-window stays open across it, so `M5` / `M101` / `M3` inside a job switches
-models between its sections with no new press. The switch is
-program-scoped: it reverts to the boot default at `M2`/`M30` and on a soft
-reset, so a job header can declare the model it needs without leaving the
-machine in it; `M101 P<n> Q1` sticks until the next switch or a controller
-restart. The stream leads the first run after a switch dark (duty 0) until
-the commanded power lands, so neither model's number is ever shipped under
-the other.
-
-**The floor is derived, never typed.** Each model has an S-range floor as a
-config key: `laser_floor_density` (default 10, the lowest density that
-still marks, putting a commanded 1 % at 10.2 % density) and
-`laser_floor_analog` (default 16, the duty this tube lases at; 3 to 14 % is
-a dead band). At every arm and every switch the controller loads the
-selected model's floor into `$35` in RAM and re-precomputes the PWM
-mapping; the stored `$35` is never written, `$$` reports the floor in
-force, and a `$35` typed by a sender is overwritten at the next arm. The
-arm and switch reports name both (`laser armed (density, floor 10 %)`,
-`laser power model set for this program (analog, floor 16 %)`), and a floor
-of 0 is honored with a note (the ladders run that way). The cooling report
-carries the model in force (`model=` on `POST /cool/state`) so the engine's
-tube-heat share follows an `M101` as well as the default.
+**The floor is derived, never typed.** `laser_floor_density` (default 10,
+the lowest density that still marks, putting a commanded 1 % at 10.2 %
+density) is loaded into `$35` at every spindle precompute - boot
+included - in RAM only: the stored `$35` is never written, `$$` reports
+the floor in force, and a `$35` typed by a sender is overwritten on the
+spot. The arm report names it (`laser armed (density, floor 10 %)`), and
+a floor of 0 is honored with a note (the ladders run that way). The
+cooling report carries the model with the job state.
 
 **Measured dose response (this bench, 2026-08-30, by the head thermopile,
 the tube current and the operator's eye on Thick Draftboard and acrylic).**
 Density delivers about half of the CW light at 80 % density, a third at
 60 %, a fifth at 45 % and a fourteenth at 30 %: the curve is the tube's
-(pulsed against CW), not the sensor's, and it is the same physics behind the
-factory's 18.9 to 79.5 % mapping with Full Power kept apart. Analog is
-close to linear above 30 % duty (0.82 / 0.68 / 0.54 / 0.37 of CW at 80 /
-60 / 45 / 30 % duty, the tube current equal to the duty) with the lasing
-knee at 20 to 23 % duty below that. The finish on acrylic is the same under
-both models, and the only visible pattern is mechanical (present under CW
-too), so the models differ in their S scale, not their mark. A per-model S
-correction (E4 in the working file) is the open item that follows.
+(pulsed against CW), not the sensor's, and it is the same physics behind
+the factory's 18.9 to 79.5 % mapping with Full Power kept apart. An S
+correction from that curve (E4 in the working file) is the open item that
+follows. Rasters hold their tonality down to ~14 pulse slots per pixel
+(508 DPI at 6000 mm/min): the dither accumulator's cross-pixel averaging
+recovers the levels, with no visible dither pattern.
 
 An S word takes effect whether or not motion is in progress. Per-segment
 updates carry the level inside a laser block, but an S executed between
@@ -319,7 +298,7 @@ on a clean re-check; FAULT leaves the hold and the gate for the operator.
 never open the Grbl socket (a connection displaces the sender), so the
 controller writes two files under `/run/forgefirm`, atomically, on
 edges: `grbl.settings` (the `$$` view, rewritten on every setting
-change, the M101 switch included) and `grbl.state` (JSON: machine state
+change and whenever the derived floor moves) and `grbl.state` (JSON: machine state
 and alarm, the sender session with peer and generation, the laser's
 armed window and dose model with its floor, the exact `[GC:...]` modal
 report, overrides, driver version, `ts_mono` for age; on change plus a
@@ -1359,11 +1338,12 @@ Open items only. Anything closed is in `CAMPAIGN-LOG.md`.
 
     **The defaults are flipped:** `laser_power_model` defaults to `density`
     with a 10 % floor (`laser_floor_density`), so a stock machine runs the
-    model and a commanded 1 % marks. The analog path remains as
-    `laser_power_model = analog` or `M101 P0` in a job, with its own floor
-    key (`laser_floor_analog`, 16); the controller derives `$35` from the
-    selected model's key at every arm and switch, so no floor is typed and
-    no mismatch exists ("Laser control (GRBL mode)" above).
+    model and a commanded 1 % marks. The analog rendering is not a
+    product mode (it fires the strike transient as a spot at every
+    beam-on; removed 2026-08-30) and survives only as the host harness's
+    conservatism reference; the controller derives `$35` from
+    `laser_floor_density` at every precompute, so no floor is typed
+    ("Laser control (GRBL mode)" above).
 
     Owed: validation at production feeds. Every ladder behind these
     defaults ran at F300 or F100, where dose per millimeter is generous and