docs(signing-key-lld): dual-audience translate pass — decision-matrix + symbol anchors

[bdchatham]

An improve-in-place /lingua Translate pass on the validator signing-key LLD — the first production translation from the Sei Agentic Mesh corpus work (Phase 3 pilot). Suggest-only, and because this doc is safety-critical (a validator double-sign is slashable and irreversible), Guardrail-6 was in force throughout: restructure for clarity, never reword a constraint.

The doc was already strongly conformant, so this is a deliberately small diff — two real improvements, nothing manufactured:

1. §6 validator legality → decision-matrix

The three SigningKey-combination paragraphs become a (combination → verdict → why) table. Every verdict (Rejected / Valid-and-expected / Valid) and every reason is preserved verbatim-in-meaning; the GenesisCeremony mutual-exclusion invariant now reads must not (was "is not"), corroborated by the return fmt.Errorf(...) block directly above it. The win is dual-legibility: a reader scans the verdict column, and an implementing agent reads three typed (combination, verdict) facts instead of inferring each verdict from a mid-paragraph adjective.

2. File anchors: drifted line numbers → symbols

Three code references had genuinely rotted since the doc was written. Re-anchored to symbols that survive refactors (all verified present on main):

was	now
planner.go:195	the NodeUpdateInProgress setCondition discipline
noderesource.go:229-447	buildNodePodSpec, buildNodeMainContainer
planner.go:411	buildBasePlan (validator path)
validator.go:17-36	validatorPlanner.Validate

What was deliberately not changed

Sections that were already conformant were left untouched. §8's cutover is single-shot by construction (no phases), so no per-phase rollback was invented — surfaced, not authored.

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Review: prose-steward adversarial fidelity pass → DOES NOT BLOCK (clause-by-clause check of the safety-critical §6 matrix; no constraint dropped, weakened, or broadened). · Linear: PLT-496 · Doctrine: Design 04 → BG-4 (Tide#146)

🤖 Generated with Claude Code

[cursor]

PR Summary

Low Risk
Documentation-only edits to an LLD; no runtime or API behavior changes, with safety constraints preserved rather than relaxed.

Overview
§6 validator legality is reframed as a three-row decision matrix (SigningKey × GenesisCeremony / Snapshot / neither → verdict → rationale), replacing prose paragraphs. The GenesisCeremony mutual-exclusion rule is stated as must not import keys from a Secret, aligned with the planner fmt.Errorf above it; other verdicts and migration/block-sync cases are unchanged in meaning.

§5 and Related work drop brittle line-number links (planner.go:195, noderesource.go:229-447, etc.) in favor of stable symbol anchors (NodeUpdateInProgress setCondition discipline, buildNodePodSpec / buildNodeMainContainer, validatorPlanner.Validate, buildBootstrapPlan, buildBasePlan validator path).

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