docs: make container CLI handoff executable

[veil-chow-fyaic]

Outcome

Makes every shipped Compose CLI handoff command executable as written and publishes the documentation-correctness repair as v0.1.0-alpha.4. Screening behavior is unchanged from alpha.3.

Root cause

The hardened image intentionally contains the package and migrations, not arbitrary repository example files. Three handoff snippets supplied a host path to the container process.

Changes

• stream request JSON through bounded stdin using docker compose exec -T app ... --request -
• align README, CLI guide, release handoff, API/package/Compose version and changelog
• add a regression assertion covering all three executable handoff documents
• update the current repository gate count to 2,081

Real verification

• documented CLI command against the running PostgreSQL-backed alpha stack: RED/HOLD, automatic_clearance=false
• authenticated REST against the same input: identical active bundle and outcome
• ./scripts/check.sh: 2,081 tests, 100% statement/branch coverage, Ruff, format, strict mypy, architecture/contract/docs/OpenAPI/build/secret/dependency gates
• regenerated 13-page A4 Chinese guide; extracted-text checks and visual review of cover, CLI/MCP/Agent, and boundary pages

Closes #56