Windows docs: add a quick start with expected durations, known failures and how to launch

[coneilen]

Is your feature request related to a problem?
Going from a clean clone to a running Windows app took most of a working session. The information exists, but it's spread across AGENTS.md, graphcode-windows/README.md and Tools/windows/PACKAGING.md. None of them says how long each step takes, what commonly fails, or how to actually launch the result.

Describe the solution you'd like
Add a "Windows quick start" section (in graphcode-windows/README.md, linked from the root README and AGENTS.md) covering:

• Prerequisites: VS Build Tools and Windows SDK, pwsh 7, winget. Note that the bootstrap installs Swift 6.3.3 via winget, which also installs Python 3.10.
• Steps with rough durations: bootstrap, Swift staging (the graphcoded build took about 220 s on the reference machine), shell build and packaging.
• Known failures and fixes:
  • Deep checkout paths hitting MAX_PATH; use a short root such as C:\gc.
  • Git long paths for providers.
  • Slow ziglang.org downloads.
  • package.ps1 requiring a release tag.
• How to launch a local build: daemon first, then the shell, with GRAPHCODE_SUPPORT_DIR. Mention the first-run onboarding dialog. Note that you should not redirect USERPROFILE.
• What validation does and doesn't prove, linking to the parity ledger.

Update the section once the quick-start script, local packaging and bootstrap issues land.

Describe alternatives you've considered
None. The doc is cheap and saves new users hours.

[coneilen]

Status audit — 2026-10-01

Classification: deferred, with no implemented quick start. Recommendation: keep open. Confidence: high.

The current graphcode-windows/README.md begins with shell architecture rather than clean-clone setup, while PACKAGING.md covers release packaging rather than an end-to-end contributor build/run route. #563, #569, and #571 changed investigation/planning documents, not the requested user-facing quick start.

Remaining acceptance criteria: document prerequisites, pinned commands, realistic durations, known-failure remedies, safe local launch, onboarding behavior, and evidence limits; link it from the root README and AGENTS.md; reconcile the supported route with #551, #553, and #557 without presenting -AllowTagMismatch as normal local development; and validate the instructions on a clean Windows checkout.

Preview priority: P2, after or alongside the underlying workflow issues. Required for broad contributor handoff, not for a controlled prebuilt-package flight.

[coneilen]

The documentation lane is active on coneilen-microsoft-windows-contributor-quick-start, stacked on PR #585's exact head e5c2772f5608e915525f94faf855a4c07e752132. It is currently bootstrapping/running the real pinned build/start/validation/stop route before documenting it. No PR exists yet, so this issue remains open; it should close only when the upper docs PR is created, exact-head CI passes, and the native stack lands.