docs: reduce AI-like writing in source JSDoc and library documentation

[roottool]

Description

Rewrites AI-generated writing patterns across source JSDoc comments and library documentation. No functional changes.

Type of Change

• Documentation (changes to documentation only)

Boundary Checklist

• This is a non-implementation change (Documentation, Tooling, or CI only)

Security & API Stability

• No security impact (forbidden keys, prototype safety unaffected)
• No changes to public API (parse, ParseResult, ParseIssue, IssueCode)
• No breaking changes; or justified with version bump rationale
• Compatible with current v0.x versioning policy

Testing

• bun run check:type:source passes
• bun run test passes
• bun run build passes

Changes

Source JSDoc (src/)

• parse.ts: replaced vague "establishes a security-focused boundary" with direct description; rewrote @param list intro as "Fails completely if any entry violates the rules below — no partial success:"
• ParseResult.ts: removed "This is a discriminated union type." (redundant with the type definition); rewrote issues: [] comment to explain why the field is kept on the success branch
• IssueCode.ts: removed intro sentence restating what the type already expresses
• forbiddenKeys.ts: removed redundant sentences describing what the array contains
• createIssue.ts: reduced to /** @internal */ (one-liner internal helper needs no further documentation)

Library Documentation

Patterns removed across README.md, AGENTS.md, CONTRIBUTING.md, SECURITY.md, CLAUDE.md, skills/README.md:

• Filler adjectives (comprehensive, robust, seamless)
• Full-sentence bold used as emphasis (e.g. **Please read these documents carefully.**)
• Period-terminated list introductions ("for the following." → "for:")
• Vague boundary marketing phrases ("establishes a predictable boundary", "security-focused boundary") replaced with direct descriptions
• Redundant authoritative-reference sentences
• Weak verb forms ("is designed to", "allows you to")

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🤖 Generated with Claude Code

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 100.00%. Comparing base (a6aeda4) to head (d963b5c).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main       #66   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            3         3           
  Lines           23        23           
  Branches         5         5           
=========================================
  Hits            23        23           

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