docs: add Cognitive Mode Switching workflow + gstack integration (v3.34.9)
- guide/workflows/gstack-workflow.md (new): Cognitive Mode Switching
pattern — 6 gears table, pre-implementation strategic gate concept,
/browse non-MCP native Chromium daemon architecture (~100ms/cmd),
full ship cycle demo. Reference impl: gstack by Garry Tan (YC CEO).
- examples/commands/plan-ceo-review.md (new): strategic product gate
template with 3 modes (SCOPE EXPANSION / HOLD SCOPE / REDUCTION)
- examples/commands/plan-eng-review.md (new): engineering architecture
gate template with Mermaid diagrams, failure modes, test matrix
- guide/workflows/README.md: add entry + 2 Quick Selection Guide rows
- guide/ecosystem/third-party-tools.md: gstack in Plugin Ecosystem
- machine-readable/reference.yaml: v3.34.9, 11 new gstack entries
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>