* fix(#619): resolve gsd-tools via runtime shim in codebase-drift-gate
The post-execution drift check ran the bare PATH binary
`gsd-tools verify codebase-drift`. On a shim-only install (gsd-tools.cjs
present, `gsd-tools` not on PATH) that exits 127, `2>/dev/null` hides it,
and the `|| echo` fallback marks the gate skipped — so codebase-drift
detection silently never runs. Non-blocking by contract, so nothing
surfaced; it just quietly stopped working.
Resolve gsd-tools through the runtime shim launcher (gsd_run) instead.
The canonical launcher preamble is now defined once in the always-run
drift-check block (the file's first gsd_run block); the conditional
auto-remap block reuses gsd_run from the workflow's shared shell scope,
keeping the file compliant with the single-canonical-preamble parity
invariant (tests/runtime-launcher-parity.test.cjs). This is the same
single-preamble pattern established by discuss-phase (#614). Non-blocking
is preserved for the drift command's internal failures via the unchanged
`|| echo '{"skipped":...}'` fallback.
Scope decision (the issue's open question): workflow step-file bash blocks
share one shell scope, so the preamble is defined once before the first
gsd_run call — matching discuss-phase and enforced by the parity test.
Regression test (bug-619-...): contract assertions (gsd_run not bare
gsd-tools; single preamble in the drift block; fallback intact) plus a
behavioral proof that runs the shipped drift-check block against a
shim-only topology and asserts the shim actually executes where the old
bare-binary form would have skipped. Red→green verified.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
* chore(#619): add changeset for codebase-drift-gate shim fix
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>
