docs: start milestone v0.7.0 (Ergonomics, Adoption & Documentation)

[sipemu]

Starts the v0.7.0 — Ergonomics, Adoption & Documentation milestone via /gsd-new-milestone.

v0.6.0 delivered full API parity and shipped to PyPI. v0.7.0 shifts from capability to adoption: type-safe, ergonomic to consume, clear on errors, clean, and fully documented.

Planning artifacts

• PROJECT.md — Current Milestone section, v0.6.0 work moved to Validated, v0.7.0 decisions logged
• REQUIREMENTS.md — 19 requirements across Type Safety / Result Ergonomics / Errors / API Consistency / Documentation / Release (100% mapped to phases)
• ROADMAP.md — 5 phases (8–12), continuing numbering from v0.6.0
• STATE.md — reset for v0.7.0
• v0.6.0 phase directories archived under .planning/milestones/v0.6.0-phases/

Roadmap

#	Phase	Requirements
8	Type Safety	TYPE-01/02/03
9	Result Ergonomics	ERGO-01/02/03
10	Errors & API Consistency	ERR-01/02, API-01/02
11	Documentation & Adoption	DOCS-05→11
12	Release 0.7.0	REL-05/06

Docs-only change (.planning/); no source or CI impact.

🤖 Generated with Claude Code

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