docs(standard): recognize the GNU-compliance (pure-FSF) posture

Add an external-compliance posture clause to §1: an artifact whose goal is to be GNU-compliant MAY declare the pure-FSF posture (pure-fsf-gnu skill), under which GNU/FSF requirements override the Standard's identity clauses (§2 naming, §11-§12 brand, §15 attribution, GitHub hosting) while the GNU-silent clauses (§6.3, §14, §3.3) stack. Closes the gap where the Standard had no external-compliance mechanism. Propagates to the published Steelbore Standard.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: UnbreakableMJ

spacecraft-standard.skill

@@ -37,6 +37,8 @@ in §16 is your audit gate — run through it mentally before finalising any out
 
 The Steelbore Standard defines the engineering principles, compliance requirements, and design conventions that govern all software produced under Spacecraft Software. The umbrella encompasses two categories of work: **Steelbore OS** — the operating system and all OS-specific artifacts (configurations, themes, OS tooling) — and **independent Spacecraft Software projects** such as Zamak, Ironway, Ferrocast, and Caliper, which are designed to work with Steelbore OS but are not OS-specific and may run on any compliant platform. Both categories are full citizens of Spacecraft Software and subject to this standard in full. Where a project-specific specification conflicts with this standard, the stricter of the two requirements shall prevail.
 
+**External-compliance posture (GNU/FSF).** A direct contradiction is not a strictness gradient: an artifact whose goal is to be **GNU-compliant** — an official GNU package, upstreamed to GNU/FSF, or hosted on Savannah — must meet GNU/FSF requirements that flatly oppose this Standard's *identity* clauses (§2 naming, §11–§12 branding, §15 attribution, and GitHub hosting). Such an artifact MAY declare the **pure-FSF posture** (the `pure-fsf-gnu` skill); in that posture GNU/FSF requirements override those identity clauses for that artifact, while this Standard's GNU-silent clauses — §6.3 signed commits, §14 UTC dates, §3.3 security-by-design — still apply and stack. Absent that declaration (the default for every Spacecraft project), this Standard governs in full and GNU conventions are adopted only where they aid interoperability (the GNU-*compatible* posture; see the `gnu-coding-standards` skill).
+
 **Standard name vs. project naming.** "The Steelbore Standard" is the canonical, stable name of *this standard*. It is independent of the projects it governs and of the umbrella organization name — the standard retains this name regardless of any future renames. The v1.7 umbrella rename (Steelbore → Spacecraft Software) and the v1.8 reinstatement of this standard's name are recorded in the changelog. Versioning of project codenames (see §2) and versioning of the standard are separate concerns.
 
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