chore: streamline development workflow

[sanohiro]

What changed

• make documentation, review, test-selection, and capability-boundary guidance proportional to the changed contract
• centralize LLVM-aware Cargo invocation in scripts/cargo.sh
• simplify the one-review/one-fix pre-PR attestation and draft-PR publication flow
• replace the aggregate full-workspace test policy with explicit owner targets
• align the remaining pkg.db prerequisite and product waves with consumer-complete capability boundaries

Why

The previous workflow repeated broad review and verification work after local findings were already closed, treated acceptance labels as PR boundaries, and accumulated operational narration in design sources. This change makes one exact review, one coherent fix, selected owner verification, and final-SHA attestation the normal publication path.

Review findings closed

• classify source-to-documentation renames as both a deletion and an addition before granting the docs-only exemption
• use GitHub CLI's built-in --jq support for PR refreshes instead of an undeclared standalone jq dependency
• cap review watchdog polling at the nearest explicit maximum or stall deadline
• bind preflight to the review log's initial HEAD/base metadata and trailing verdict even when inspected fixtures contain inert marker-shaped text

Validation

• bash scripts/test-pr-workflow.sh
• scripts/test-pr.sh through the final preflight (all bounded library, interface, formatter, and M0 owners)
• scripts/cargo.sh clippy --workspace --lib --bins --locked -- -D warnings
• git diff --check origin/main...HEAD

The ordinary macOS target first stalled in _dyld_start before the codegen owner. The final atomic preflight passed in a dedicated CARGO_TARGET_DIR; the incomplete host attempt is preserved under .git and is not reported as a test failure.