ExcelCannon code standards

A tool whose pitch is “understand a workbook's complexity quickly” publishes its own. The limits live in standards.toml; each row is read from the outcome one check left behind, so the Measured column names the host and commit the number came from — coverage is measurable only in the Linux container, the .NET gates only on Windows, and this page is the union of what each measured. Every row is gated at zero violations: a single breach fails the gate.

Two rows read differently from the rest. coverage.lines and coverage.test_lines are percentages, and they split one export: product lines, and the lines inside inline #[cfg(test)] modules, which are covered by construction and would otherwise flatter the first number. dotnet.coverage_shortfall is a shortfall in percentage points rather than a coverage figure — every other row is a count to drive to zero, so 100 there means no coverage at all.