docs: verify Windows PowerShell install path

[mori-ikuri]

Change

• Add a copy-pasteable Windows PowerShell install and verification guide.
• Link the guide from the README manual-install section.
• Make the public-claims validator path-safe on Windows with fileURLToPath().

Related issue

Closes #13.

Evidence

Verified on 2026-08-25 with:

• Windows 10.0.19045.7663
• PowerShell 7.6.4
• Node.js 22.23.2
• npm / npx 10.9.8
• skills CLI 1.5.23
• Codex desktop 26.818.8289.0
• StyleSeed 4.1.0 at f064c75

Representative redacted output:

codex  Agent detected — installing non-interactively
Source: https://github.com/bitjaru/styleseed.git
Found 23 skills
Installed 23 skills

SKILL_ROOT_PRESENT=True
SKILL_COUNT=23
ROUTER_PRESENT=True
name: styleseed
ENGINE_VERSION=4.1.0
ENGINE_REVISION=sha256:f563a15b158ecef506f213c45ef54a71b34b4b1410c92529673b97ab34840772
SS_LEARN_PRESENT=False
EXCLUDED_MATCH_COUNT=0

The fresh checkout used core.symlinks=true; .agents/skills was a symbolic link. Checkout policy verification:

i/lf    w/lf    attr/text=auto eol=lf    scripts/validate-skill-contracts.mjs

Required checks:

node scripts/test-public-claims.mjs  PASS
node scripts/validate-engine.mjs     PASS
git diff --check                     PASS

Type

• Documentation, example, or translation
• Regression fixture or bug fix
• Design rule or palette
• Skin, component, or pattern
• Grammar or adapter
• Agent skill or packaging
• Other tooling

Checklist

• I changed the maintained source rather than only a generated mirror.
• I ran the smallest relevant checks from CONTRIBUTING.md.
• I reviewed every changed line, including AI-assisted output.
• Visual evidence is not applicable to this documentation/path-handling change.
• I kept version, release, and deployment files unchanged.

Scope is limited to README.md, docs/WINDOWS-INSTALL.md, and scripts/test-public-claims.mjs.

[vercel]

@mori-ikuri is attempting to deploy a commit to the bitjaru Team on Vercel.

A member of the Team first needs to authorize it.

[YAYLABS-Snoo]

Reviewed exact head ae41558. Local verification: test-public-claims PASS, runtime tests 57/57 PASS, validate-engine PASS, and git diff checks clean. The fileURLToPath fix correctly addresses Windows file-URL conversion without expanding the documentation scope. The Windows installation evidence is contributor-reported and clearly versioned. GitHub Actions run 32802744998 also passed. Approved.

[bitjaru]

Maintainer verification on exact head ae41558: test-public-claims PASS, runtime tests 57/57 PASS, validate-engine PASS, generated and diff checks clean, and GitHub Actions run 32802744998 passed. The Windows installation evidence is contributor-reported and clearly versioned. Approved.