[linuxnow]

Part of #131. Three of its parts, in small commits; the Zynthian gap verbs (preset save/show/load on the CLAP worker, parameter feedback, MIDI learn) and the union-narrowed world itself are a follow-up on #131, not here.

Chain floor 1 (8a10634). chain_members_min (1) is a declared constant, with line_words_max (64), the word count verbs.c reads a line to. The grammar in verbs.c and the supervisor's own guard both read the floor from the header, so a chain of one runs in a worker of its own; a chain of none stays outside the grammar (-902). a_chain_of_one_runs_in_a_worker_of_its_own_and_a_chain_of_none_is_refused asserts both answers, the chain_formed 5 <worker> 21 event, the worker told chain 5 21, the member's parameter kept, and chain_clear giving it back a worker of its own. Three sabotage arms put the floor of two back in the header, the grammar and the supervisor; each turns it red.

The host verb table (d11f368, 30a1c7a). PHD_HOST_VERBS in protocol.h gives every verb a controller sends the daemon a level (required, optional, absent) for four profiles: lv2-worker, clap-worker, console, zynthian. The mod-ui rows carry the ruled starting values, with MIDI learn and CV addressing required of the CLAP worker and of Zynthian (ruling of 2026-10-22). protocol-gen writes the table into protocol/plugin-hostd.json (host_profiles, host_verbs, both in the schema) and into the README. tests/verb_table.py (make check-verb-table, in make test) builds a program against the header and holds the table to mod-host.json's commands, PHD_VERBS and PHD_INSTANCE_VERBS: a verb with no row, a row twice, a row for a verb nothing declares that is not absent everywhere, and a verb the daemon answers itself that is not required of every profile each fail. Four sabotage arms (a row dropped, a verb added to PHD_VERBS with no row, chain made absent for the console, a verb mod-host never had made required) each go red.

For review: the 34 rows outside the 35 mod-ui verbs are this tree's proposal, not a ruling. Daemon verbs are required everywhere (the daemon answers them whatever the worker); disconnect, set_bpm, set_bpb and quit are required; the other mod-host commands and the instance verbs are optional.

LV2 chains under require_pins (b31be14, ec835c5). The chain note now states the union-narrowed world as required, where it had an open question, and records the -101 that a chain member gave in a single-bundle LV2_PATH in omx-clap-core's Stage 0 bench. The chain verb's -501 clause says that every LV2 plugin, a chain of one included, is refused while require_pins is on, until a chain's worker gets the union of its members' bundles. under_require_pins_a_chain_of_lv2_members_is_refused_until_its_worker_gets_the_union_of_their_bundles holds that refusal for a chain of one and of two pinned LV2 members: nothing moves and no worker is told. A sabotage arm that drops the guard turns it red. narrow_world still takes one uri, so the union is not built here.

Run in a Fedora 44 container (mod-host-protocol-devel 0.10.6, omx-contract-devel 3.0.0, no network), after make clean and a build: make test green, including plugin-hostd tests ok (0 failed), generated files are current, the schema check, the C consumer, the verb table and the verbs contract. make private-refs was green on the host. python3 tests/sabotage.py in full: 225 arms caught, 6 skipped (no OMX_CLAP_HOST), and 1 survived, "worker_env is not applied to a running worker". Run alone three times on this branch, that arm went red each time, and it also goes red on main. It looks like a timing flake under the load of the full run, not something this branch changed, but that is not proven.

Not run: the jack, lv2 and real-worker tiers (test-jack, test-lv2-adapter), which need JACK and the real workers. The README half of the verbs contract was skipped because no mod-host checkout was present. No bench was run.