Module mode 

Compatibility Mode resolution.

Per plan.md AD-004 and spec.md FR-021..FR-023:

Resolves the CompatibilityMode for an invocation once at startup at zero per-line cost. Precedence (highest first):

1. Explicit --no-strict / --no-moreutils-compat flag → Default
2. Explicit --strict / --moreutils-compat flag → Strict
3. RUSTY_TS_STRICT env var (1/true/yes = on; anything else = off)
4. argv[0] basename auto-detect: ts (or ts.exe stripped on Windows) → Strict
5. Default

Encoded as a single pure function resolve(...) so the precedence is testable in isolation (HINT-002 — the precedence ladder lives in exactly one place).

Enums

CompatibilityMode

The resolved compatibility-mode posture for the invocation.

ExplicitChoice

Explicit user choice from the CLI flag layer.

Functions

argv0_basename

Extract the argv[0] basename, stripping a .exe extension on Windows.

resolve

Resolve the compatibility mode from the three inputs.