task: populate the empty Spec Kit constitution with project-specific principles

[dgarros]

Need

The Spec Kit constitution (.specify/memory/constitution.md → dev/constitution.md) still contains only the default starter template — every principle, section, and governance rule is an unfilled placeholder ([PRINCIPLE_1_NAME], [GOVERNANCE_RULES], [CONSTITUTION_VERSION], …).

Spec Kit treats the constitution as the source of quality guardrails that specs, plans, and implementations are checked against (used by the constitution, critique, analyze, and review steps). While it stays empty, every feature run through Spec Kit on this repo has no project-specific quality bar to enforce — the SDK's conventions (async/sync dual pattern, type hints everywhere, invoke format lint-code, docs-generate obligations, never editing generated protocols.py, testing expectations, …) live only in AGENTS.md and are never surfaced to the Spec Kit gates. This risks Spec-Kit-produced features drifting from the standards the rest of the codebase holds to.

Context

• The file is a symlink: .specify/memory/constitution.md → dev/constitution.md.
• Current content is the unmodified Spec Kit starter template (placeholders throughout, version [CONSTITUTION_VERSION]).
• The conventions a constitution would need to reflect are already documented in the root AGENTS.md and the subdirectory guides (docs/, ctl/, pytest_plugin/, tests/).
• /speckit.constitution is the intended tool for authoring this file and keeps the dependent templates in sync.

References

• File: dev/constitution.md (via .specify/memory/constitution.md)
• Project conventions: AGENTS.md