Law 0 root (PR1): the root's prod source names no plane, transport or auth instance

[MattJackson]

Law 0 root lane, PR1 of 3 (prod source). BUSBAR-1.6.0.md l.104-120, l.172-182: the composition root's Rust source names no instance; customer-visible bytes stay v1.5.5's.

Values read off declared rows (each with a RED):

• Line carrier: the linked transport claim whose claim row opens unit 0 on its FIRST LINE (TransportFacts.lines in plugin-loader, LinkedTransport.lines from linked_gen.rs, root::serve::lines::line_carrier). Two such claims refuse the boot (lines::refusal, main.rs). BUSBAR_<PLANE>_<CARRIER>_CREDENTIAL and the serve's stderr sentences are spelled from the plane's and the carrier's keys, so they keep 1.5.5's bytes. RED: root/tests/serve_lines.rs (neutral doubles: the carrier is whatever the row declares; two are refused; the credential variable is spelled from both keys; the build's carrier is the one its linked rows declare).
• Request wire (root listener log scheme, admin and gauntlet arrival chains): the admin plane's declared claim transport (root::listener::REQUEST_WIRE, units_admin::ADMIN_TRANSPORT). RED: units_admin arrival test checks the chain against admin_codec::claims::CLAIMS.
• Operator credential provider word: the linked-name of the row the manifest's new [package.metadata.busbar.operator-auth] table names. Packaging states it, linked or not, so the 1.5.5 "built WITHOUT the auth-… feature" refusal still spells it. RED: the_operator_provider_is_the_row_the_manifest_names checks the named row is the only linked row whose Statement states FACT_OPERATOR, with the same principal (kinds::auth::operator_principal).
• --list-plugins header: v1.5.5's line (main.rs:419-422) as one constant. RED: the header heads the row format's columns.

Other changes:

• Test cfgs feature = "auth-…" become linked_axis_auths.
• Collision-only renames: the trust decision binding becomes ruling; ProviderAuth as Style; Served::tcp becomes accepted.
• Plane-naming prose reworded.

Gate: kind_isolation/matrix.rs gets EXPORT_STREAMS_KEY. An export entry's frozen 1.5.x streams: [ key (v1.5.5 config/migrate_export.rs:17) is the export projection, not the plane, told apart by its list value. A streams: keying a mapping still counts. It has a selftest green/red pair, like BARE_WORD_COLLISIONS. The FILE exemption was not needed: the header constant carries no file literal.

law0 rows lowered to the measure:

crate	axis	before	after
busbar	auth	49	43
busbar	export	15	14
busbar	instance:auth	24	22
busbar	instance:export	33	32
busbar	instance:secret	35	34
busbar	plane	826	774
busbar	transport	224	192
busbar-kernel	plane	1122	1100

The kernel plane drop is the 22 export streams: [ keys.

Left in place to avoid same-hunk edits (rule 20):

• adapters.rs UpstreamCode: P3 FLIP-A2A: the a2a plane served through its door; busbar-a2a deleted (stacked on #778) #787 (carrying row 68: the breaker reads a plane fault at the far end (stacked on #561) #778) rewrites the breaker port into fault readings.
• main.rs l.1341: held by row 159: stdio serve mode drains the journal lane and plane-record write-behind before exit (audit busbar-src #1, HIGH) #839.
• linked.rs program-member comment: held by row 166 PR2b: a program's environment secrets resolve at declaration and are held; a spawn resolves nothing #865.
• door_steps.rs and serve.rs comments: held by P3 FLIP-A2A: the a2a plane served through its door; busbar-a2a deleted (stacked on #778) #787.

[MattJackson]

Rule 20 note from #1030 (row 155): disjoint hunk in crates/busbar/src/root/door_steps.rs (DoorSteps gains usage_tap_fault after attempting, plus a doc line on translations). A test merge is clean.

[MattJackson]

Rule 20 note from #1031 (row 155, draft): one more disjoint hunk in root/door_steps.rs (kernel_sections' limits json gains request_body_max_bytes, plus its doc). A test merge is clean.