docs: add Windows installation instructions to README

[farouk-allani]

Added Windows installation instructions for the CLI.

Issue

No issue required — docs-only change, per the exemption list in ISSUES.md.

What this changes

Adds a Windows entry to the Install section of the README.

.goreleaser.yaml already builds and publishes Windows binaries for amd64 and
arm64 on every release, but the Install section lists only Homebrew, go install,
and a generic "download from Releases." On a clean Windows box the first two are
unavailable, and the third doesn't say which asset to take, where to put it, or
how to get it on PATH.

The new entry names the exact artifact, gives the extract-and-PATH commands, and
notes the SmartScreen prompt on first run — which is the step most likely to look
like a broken binary rather than an OS warning.

Nothing a reader wouldn't predict from the title: no new dependency, no changed
default, no credential handling.

Scope

One change, one section, one file. Nothing here could be reverted independently.

How it was verified

Ran the documented steps end to end on Windows 11 Pro (PowerShell 5.1) from a
clean state: downloaded the release zip, extracted with Expand-Archive, added
the folder to the user PATH, restarted the terminal, and confirmed
kh version resolves. SmartScreen did prompt on first run, which is why the
Unblock-File note is included.

No tests: docs-only, no Go code touched, so make lint / make test and
go generate ./docs/ are unaffected.

---

• Targets main
• Title carries the issue number, or an exemption applies — docs exemption
• make lint and make test pass — N/A, no Go code changed
• go generate ./docs/ run and committed, if a command or flag changed — N/A

[suisuss]

What this changes

Adds a Windows install entry to README.md's Install section (11 lines, one file): download kh_<version>_windows_amd64.zip from Releases, Expand-Archive it into %LOCALAPPDATA%\Programs\kh, persist that folder onto the user PATH, restart the terminal, run kh version, and unblock the exe via Unblock-File if SmartScreen intervenes on first run.

Does it match the description

Yes. The PR body's description of scope and verification lines up exactly with the diff - nothing more, nothing less.

Blocking

None on substance. The content is correct: I downloaded the live kh_0.14.1_windows_amd64.zip release asset and verified kh.exe sits at the archive root, so both the extract path and the later Unblock-File path in the doc are accurate, not just plausible-looking. .goreleaser.yaml confirms Windows builds are already shipped on every release, and no code-signing step exists, so the SmartScreen callout is a real condition rather than invented friction.

Mechanical - actionable as-is

• Retitle to docs: add Windows installation instructions to README. The repo's check-issue-link CI job is currently failing on this PR because the title carries neither a conventional-commit type prefix nor an issue reference. docs/chore/style titles are auto-exempt from the issue-before-PR gate per ISSUES.md, and this change genuinely qualifies (new instructions for an already-shipped build target, not a correction to an existing behavior claim) - retitling makes the exemption apply automatically instead of sending you to file an issue you don't need. Precedent: #88, #94, #98 all use this exact docs: <lowercase description> style.
• Minor formatting: the diff leaves a double blank line before ## Auth - collapse to one for consistency with the rest of the file.

With the team

docs/quickstart.md has its own parallel Install section (Homebrew, Linux headless with checksum verification, Go install, generic "Binary download... add to your PATH") that still has no Windows-specific entry after this merges. Not this PR's job to fix - you scoped it to README.md only, which is a defensible unit - but worth a follow-up issue if the team wants Windows guidance in both places rather than just the README.

Verdict

changes-requested - purely procedural (retitle to unblock CI), not a substance objection. Content is accurate and verified.

[suisuss]

Pushed the blank-line fix and retitled to docs: so the issue check passes - your reasoning in the description was right, docs-only changes are exempt, but the exemption is read off the conventional-commit prefix in the title and the title had none.

The install steps themselves I verified against the 0.14.1 Windows release asset earlier; nothing to change there.