Normalize declaration ordering across the kb package (helpers at end, alphabetized)

[williamthorsen]

Problem

Intra-file declaration ordering in packages/kb/ is inconsistent. Some test files place module-level helper functions above their describe block, contrary to the house style of helpers-at-the-end. Some production files have non-alphabetized exports or helpers, an exported function stranded inside the // region | Helpers block (check.ts, create.ts), or a helper stranded among exports with no region wrapper (type-guards.ts, yaml-position.ts). The effect is that locating a function means guessing each file's ad-hoc ordering instead of relying on one predictable rule.

This issue originally scoped the work to test-file helper relocation; it is broadened here to a package-wide ordering pass, since the same inconsistency exists in production files and the goal is one uniform, ergonomic ordering rule.

Context

• The package already uses a // region | Helpers convention to demarcate trailing non-exported helpers — including for single helpers (scaffolding.ts, exists.ts, load-schema.ts). "Always wrap helpers in a region" therefore codifies existing practice rather than imposing a new style.
• The separator-banner cleanup raised during planning has no targets in kb — a whole-repo scan found exactly 2 such lines, both in an unrelated agents example file. Other house-style rules (leading-verb names, imperative comments, sentence case, doc descriptions) already scan clean in kb. The actionable work is declaration ordering only.
• function-declaration hoisting makes the test-file relocation runtime-inert; every helper in scope is a function declaration, not an arrow const.

Proposed solution

Apply one ordering policy to every .ts file under packages/kb/src:

1. Exported declarations first. The production entry point leads when a module has exactly one production-consumed export (e.g. runCheck, runCreate); otherwise exported declarations are alphabetized case-insensitively. Test-only exports sort alphabetically among the rest — no separate tier.
2. Non-exported helpers last, inside a // region | Helpers block (always present when helpers exist), alphabetized within the region.
3. Test files: relocate module-level helper functions below the describe block(s), wrapped in // region | Helpers, alphabetized. Module-level test data and constants (fixture maps, sample strings) may remain at the top.

This is pure source reordering plus region-marker insertion; no runtime behavior changes.

Acceptance criteria

Must have

• In every kb .ts file, non-exported helper functions appear after the exported declarations, inside a // region | Helpers block, alphabetized within the region.
• In every kb .ts file, exported declarations precede helpers; the sole production entry point leads when one exists, and remaining exports are alphabetized case-insensitively.
• In every kb test file, module-level helper functions are placed after the describe block(s) and wrapped in // region | Helpers; module-level test data and constants may remain at the top.
• No behavior change: the full kb suite passes unchanged, and lint, typecheck, and format are clean. (Serves as the test criterion — existing tests cover the reordered code; no new behavior is introduced.)

Should have

• A scan for helper-function declarations preceding the first describe in any kb test file returns nothing, confirming the suite is fully aligned.