fix(#2285): wire claude-orchestration Workflow backend into execute-phase (#2314)

The claude-orchestration capability (#1143) shipped registered 'active'
but fully inert: detectWorkflowBackend/emitWorkflowScript had no caller
outside their own CLI router, and execute-phase.md declared an
execute:wave:pre hook point that the workflow body never rendered — so
claude_orchestration.enabled:true had zero effect on real runs.

Approach B (maintainer-chosen):
- execute-phase.md now renders the execute:wave:pre hook
  (gsd_run loop render-hooks execute:wave:pre) at a new step 2.75,
  immediately before each wave's Agent() dispatch — fixing the latent
  dead-hook gap for any pre-wave capability.
- Move the claude-orchestration contribution execute:wave:post ->
  execute:wave:pre (a pre-wave backend selector belongs before dispatch,
  not after); rename fragments/execute-wave-post.md -> execute-wave-pre.md
  with prose instructing the orchestrator to call resolve-wave-dispatch
  before step 3. Unrelated wave:post contributions (ui.safety-gate, drift,
  external-job, mempalace) untouched.
- New .cts seam resolveWaveDispatch(input) composes detectWorkflowBackend
  + emitWorkflowScript into one {backend:'inline'|'workflow', ...} result;
  exposed as gsd-tools claude-orchestration resolve-wave-dispatch. This is
  a real non-CLI-router, non-test caller of both functions.

Fail-closed: any gate miss (disabled, non-Claude runtime, Workflow tool
absent, SDK below floor, execution_backend:inline, malformed input) or an
emit failure resolves to inline with a byte-identical result shape — no
regression to the default-off execute-phase path.

Regression tests (tests/fix-2285-*) cover happy-path activation + SDK-floor
BVA, the fail-closed gate-miss table with detectWorkflowBackend parity, a
fast-check composition property, capability.json contribution assertions,
and a source-contract guard that execute:wave:pre is now actually rendered.
Dependent registry-shape assertions updated in-scope.

Co-authored-by: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

tests/slurm-adapter.test.cjs

@@ -2,9 +2,12 @@
 process.env.GSD_TEST_MODE = '1';
 
 // Refinements for issue #1164 (PR #1998 follow-up):
-// - A: document the execute:wave:post choice (wave:pre is declared but not
-//      dispatched by execute-phase.md; wiring it is a core-loop change #1164
-//      puts out of scope).
+// - A: document the execute:wave:post choice (at the time of #1164, wave:pre
+//      was declared but not dispatched by execute-phase.md; wiring it was a
+//      core-loop change #1164 put out of scope. #2285 later wired wave:pre —
+//      see gsd-core/workflows/execute-phase.md step 2.75 and the
+//      claude-orchestration capability, which moved to wave:pre for that
+//      reason).
 // - B: external_job.artifact_dir is now consumed by the adapter (was declared
 //      but unused).
 // - C: external_job.submit_timeout_ms / poll_timeout_ms are now read from