Add proofread + readability checks, severity tiers, Vale prior-art note

[bdelanghe]

Follow-up to #5. Covers the rest of the cold-read findings beyond AI-isms — "was this even proof-read?" and "why am I reading this?" — and adopts the one good idea from the Vale prior art (severity tiers). Prior-art adoption tracked in #6.

New prose checks (deterministic, uncached, every symbol)

• proofread() — high-confidence mechanical slips that spell/grammar miss: doubled words (the the), double/stray spaces, space-before-punctuation, missing space after a comma, repeated punctuation (!!), mixed straight + curly quotes, leading/trailing whitespace. Conservative by design — every rule is a real slip.
• readability() — copy a reader bounces off: over-long sentences (>28 words), and for body/meta, genuinely dense prose by Flesch reading-ease. A deterministic proxy for "I didn't get through this."

Quality fixes

• spellCheck() no longer flags English contractions (isn't, we're) as misspellings — removes a real source of false "spelling" noise.
• AI-tell lexicon expanded from the Wikipedia Signs of AI writing / vale-signs-of-ai-writing corpus (furthermore, moreover, meticulous, pivotal, landscape of, …).

Severity tiers (à la Vale)

Findings now render in tiers, sorted: ✗ correctness/honesty (ungrounded, typos) · ⚠ ai-ism/proofread · · suggestion. Wired in audit.mjs.

Parity + docs

• anthropic.mjs — the keyed LLM auditor is told the proofread + readability rules too.
• README.md — documents the new checks, the tiers, and the Vale prior art (links Adopt Vale's AI-tell rules instead of hand-maintaining the lexicon #6).
• test.mjs — covers proofread, readability, and the contraction fix.

Verification

node test.mjs passes. Sample tiered output on the demo catalog:

  ✦ pdp.body.aiism       [body    ] 10/10
       ⚠ ai-ism: "isn't just a frame — it's" — antithesis "it isn't X — it's Y" cadence
       ⚠ ai-ism: "the easy part" — "the [easy/hard] part" framing
       ⚠ ai-ism: "Fast, simple, and beautiful" — rule-of-three triad; vary it
       · grammar/style: "just" — "just" can weaken meaning

(The contraction fix means isn't no longer shows up as a spelling error here.) As with #5, full node audit.mjs was verified locally with stubs for the network-blocked JSR deps; CI has JSR access.

🤖 Generated with Claude Code

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Generated by Claude Code