docs: docs-as-code wiki tree (Phase 36)

[OgeonX-Ai]

Summary

• Adds docs/wiki/{Home,Architecture,Operations,Decisions}.md — docs-as-code wiki tree (GitHub native wiki tab intentionally not used).
• Architecture.md documents the workstation contract (stack.manifest.json), the preview-first plan/apply engine, the managed-state safety model, and doctor.ps1 readiness reporting, with a repo-specific Mermaid diagram plus a codex:generate-image placeholder matching the root docs/VISION.md house style. Also clarifies this repo's doctor.ps1 readiness sweep is distinct from the root PersonalRepo workspace's separate scripts/workspace-health.ps1 control-plane sweep (Phase 34) — verified no workspace-health.ps1-named script exists in this repo before writing that distinction.
• Operations.md documents verified Invoke-Quality.ps1/setup/upgrade/repair/uninstall commands and CI gate steps; notes no coverage-percentage gate exists (composite pass/fail gate instead).
• Decisions.md indexes all four phase directories (with plan counts) and the ADR convention.

Test plan

• Mermaid block reviewed for GitHub-renderable flowchart subset
• Grepped this repo for workspace-health before drafting Architecture.md — none found, so the page correctly attributes that sweep to the root workspace repo instead
• All internal links verified against files present on this branch

🤖 Generated with Claude Code

[chatgpt-codex-connector]

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