chore: release v0.7.0

[Brescou]

Description

Release v0.7.0 — version bump (pyproject.toml 0.6.2 → 0.7.0, uv.lock refreshed) and CHANGELOG cut: the Unreleased section becomes [0.7.0] - 2026-07-16.

Minor bump per semver: this release adds features (MCP server with new /mcp endpoint, MCP_SERVER_ENABLED flag and mcp extra; new EMBEDDING_* settings and langchain-postgres dependency) and changes observable behavior (cost_usd now 0.0 instead of null on typed routes in mock mode).

Release highlights (full details in CHANGELOG):

• MCP server — every domain pack auto-exposed as an MCP tool, sharing the typed REST execution path (budgets, compliance gating, validation).
• Deterministic mock cost accounting — consistent cost_usd, and budget 402 now testable without an API key.
• Explicit embeddings factory + migration to maintained langchain_postgres.PGVector.
• CI hardening — pyright now type-checks with all extras installed; mock-mode pack evals gate every PR.

After merge: tag v0.7.0 on main and publish the GitHub release (title and notes ready).

Checklist

• Description above explains the change and its motivation.
• Tests added or updated for the change (make test passes locally). — Version/CHANGELOG only; API test subset run locally (66 passed), full suite unchanged.
• Lint and format pass (make check, i.e. ruff check . + ruff format --check .).
• Docs updated if behavior, config, or public API changed (README, docs/, .env.example, CHANGELOG.md).
• No secrets, API keys, or credentials included in this diff.