Wait for PostgreSQL readiness before local start success

[sdairs]

Summary

• Wait for pg_isready inside the managed container before fresh and resumed local Postgres starts print credentials or return success.
• Bound readiness at 30 seconds, keep the probe detached from CLI stdio, and include the last 50 container log lines for immediate exits and timeouts.
• Return readiness failures through the normal command error path so telemetry records failure; clean up failed fresh starts and stop failed resumed starts for retry.
• Add deterministic fake-Docker unit and subprocess coverage, and make the Docker integration script rely on the start readiness guarantee.

Tests

• cargo test -p clickhousectl (754 passed)
• cargo test -p clickhousectl postgres_readiness (focused readiness coverage passed)
• cargo test -p clickhousectl --test local_postgres_readiness_test (3 passed)
• cargo clippy -p clickhousectl --all-targets -- -D warnings (passed)
• cargo build -p clickhousectl (passed)
• cargo fmt --all -- --check (passed)
• CI local postgres edge cases Docker integration (passed)
• Local Docker integration not run: configured OrbStack socket was unavailable

Stack

Position 2 of 2 (top), based on #486.

• Validate local Postgres start options before Docker work #486 validates local Postgres start options before Docker work.
• This PR adds PostgreSQL-level startup readiness.

Closes #457