bench: every board-runnable tool ported to the bench page

The remaining bench diagnostics run from forgetest's #bench tab. The
tools that also run from a LAN host share scripts/bench/gfbench.py:
GF_HOST names a remote machine (host mode, sysfs through ssh, Grbl and
forgectrl over the LAN); unset, the tool runs on the board itself
(local mode, sysfs directly, everything on 127.0.0.1), which is how the
page runs them - with GF_HOST=127.0.0.1, the panel token in GF_TOKEN
and their data files under <data>/bench/ (FORGETEST_BENCH_DATA). The
helper also reads a machine setting from forgectrl, or from the settings
file on the board while forgectrl is stopped.

Ported: pwm_sweep / pwm_hold (scope = a takeover; the latch relocked,
the write refused if FIRE or LASER_ON reads active), pwm_stream_test
(PASS/FAIL exit), flow_characterize, flow_recheck_char,
flow_warm_validate and flow_matrix (takeovers: forgectrl owns the
thermal hardware, so the page's takeover replaces the tools' own
controller stop/restart, whose command line predated the supervisor;
results and logs in the bench data directory), flow_sustained,
fan_test, temp_calibrate (dry; watch bounded in seconds; the threshold
and the coolant conversion from the shared code), flow_escalate_drill
(cool_confirm_max_s shortened through forgectrl's settings for the
drill and restored; the setting's minimum is the default budget), and
live_fire_drills (<drill> [S] [F], all six drills, host from GF_HOST,
token from the board). flow_matrix joins the registry. What stays
unported cannot run against the machine at all: the two null-sink CI
harnesses and the .puls decoder.

Runner: a scope tool runs inside the takeover wrapper; the bench
environment above is passed to every tool. Tests: test_bench_registry
(registry <-> scripts/bench consistency, every ported tool builds its
command line, every script compiles, gfbench host/local modes) and the
server test (scope tool takeover, the environment reaching the tool).
Local mode smoke-run on the bench (temp_calibrate watch, setting, token)
from /tmp, removed after.

No catalog consequence: bench tools are not image components (dev-only
forgetest); the acceptance catalog is unchanged.

docs/ACCEPTANCE.md

@@ -203,10 +203,21 @@ change author's judgment (rule 1).
 
 The same daemon serves `#bench`: the registry of the bench tools
 (`scripts/bench`, installed under `/usr/share/forgetest/bench/`), each with
-its safety class (`dry`, `takeover`, `live`, `scope`), argument form, and
-last run. A ported tool runs as a subprocess with the output on the page;
-unported tools are listed with Start disabled. Bench runs are recorded in
-`/data/forgetest/bench.jsonl` and never enter a campaign.
+its safety class, argument form, and last run. The classes: `dry` (reads
+or dry motion, forgectrl stays up), `takeover` (forgectrl and the
+controller stopped for the run, the pulse device free, the same wrapper
+the takeover tests use), `scope` (a takeover whose result only means
+something with the named instrument on the bench), `live` (emission
+possible; the operator acknowledgment and the physical arm press). A tool
+runs as a subprocess with the output on the page and, on the board, the
+machine as `GF_HOST=127.0.0.1`, the panel token in `GF_TOKEN`, and its data
+files under `/data/forgetest/bench/` (`FORGETEST_BENCH_DATA`); the same
+scripts run from a LAN host with `GF_HOST` set (`scripts/bench/gfbench.py`,
+`scripts/bench/README.md`). Every board-runnable tool is ported; the entries
+that stay unported are the CI harnesses of the null-sink controller and the
+factory `.puls` decoder, which do not run against the machine at all - they
+are listed so the catalog of what exists is complete. Bench runs are
+recorded in `/data/forgetest/bench.jsonl` and never enter a campaign.
 
 ## Layout
 
@@ -221,6 +232,7 @@ unported tools are listed with Start disabled. Bench runs are recorded in
       bench.py / coverage.py     bench registry + subprocess runner; the lint
       suite/                     the catalog, one module per subsystem
     forgetest/tests/             host unit tests (python3 -m unittest discover -s tests)
+    scripts/bench/               the bench tools (+ gfbench.py, the board/host helper)
     scripts/acceptance-gate.py   the gate
     scripts/manifest-from-tree.py  manifest from the recipe pins (CI, workstation)
     releases/v<version>/         the committed artifacts