Stabilize Windows CI and refresh project documentation

[harder]

Changes

• Give the Windows subprocess-cancellation timing test scheduling margin while keeping its 10-second bound far below the child process's 30-second natural exit.
• Correct stale built-in Doctor/help text and public usage documentation after the switch to a fixed GitHub CLI minimum and one gh skill smoke check.
• Replace obsolete design, decision, and multi-branch audit notes with a concise current architecture guide; update contributor, agent, workflow, rollback, and site docs.
• Document the actual ProtectMain configuration: it targets the default branch and requests Copilot review on new PRs, but does not require PRs/checks or review later pushes/drafts.

Verification

• dotnet restore --locked-mode
• dotnet build --configuration Release --no-restore
• dotnet test --configuration Release --no-build --verbosity normal (830 passed on Windows ARM64)
• dotnet format SkillView.sln --no-restore --verify-no-changes
• node --test .github/scripts/critical-dependencies.test.js .github/scripts/critical-dependency-assessment.test.js (9 passed)
• python site/build.py and node --check site/app.js
• git diff --check

The failed Pages workflow was also rerun successfully; no workflow change was needed for GitHub's hosted-runner error.

[Copilot]

Copilot review overview

🟢 Approval recommended

The documentation and display-text updates are low risk, and the adjusted timing assertion remains bounded below natural process completion.

Review effort: Balanced
Findings: None

What changed in this PR

Stabilizes SkillView’s cancellation test under CI load and refreshes documentation to reflect the current implementation.

Changes:

• Raises the cancellation-test bound to 10 seconds, below the child’s 30-second natural exit.
• Corrects Doctor/help text and documents the fixed GitHub CLI minimum.
• Consolidates architecture guidance and clarifies testing, contribution, and branch-rule documentation.

File	Description
tests/​SkillView.Tests/​Subprocess/​ProcessRunnerTests.cs	Adds scheduling margin to cancellation timing.
tests/​SkillView.Tests/​Cli/​CliDispatcherHelpTests.cs	Checks updated CLI compatibility wording.
src/​SkillView.Core/​Cli/​CliDispatcher.cs	Corrects Doctor output, help text, and comments.
site/​docs.html	Clarifies usage-guide coverage.
docs/​usage.md	Updates Doctor descriptions and install options.
docs/​superpowers/​specs/​2026-05-20-skillview-workflow-first-ux-design.md	Removes obsolete design notes.
docs/​runbooks/​release-rollback.md	Removes a version-specific deletion example.
docs/​reviews/​adversarial-concurrency-resource-cancellation-audit-2026-08-28.md	Removes historical audit notes.
docs/​decisions.md	Removes outdated decision documentation.
docs/​architecture.md	Adds a concise current architecture guide.
CONTRIBUTING.md	Refreshes architecture and build guidance.
AGENTS.md	Condenses testing and framework guidance.
agent_docs/​tui-pty-testing.md	Updates startup detection guidance.
agent_docs/​running-tests.md	Refreshes runner and automation-check instructions.
.github/​workflows/​README.md	Documents actual ProtectMain behavior.
.github/​copilot-instructions.md	Clarifies when fresh reviews need manual requests.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.