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/execute-wave-post-gate-pipeline-e2e.test.cjs

@@ -629,17 +629,29 @@ describe('F. Real registry execute:wave:post shape — guard against accidental
       `ui.safety-gate onError must be 'halt'; got ${uiGate.onError}`);
   });
 
-  test('[happy] real registry: execute:wave:post has no steps and 3 contributions (claude-orchestration executor + external-job executor + mempalace capture-problems)', () => {
+  test('[happy] real registry: execute:wave:post has no steps and 2 contributions (external-job executor + mempalace capture-problems)', () => {
     const point = realRegistry.byLoopPoint['execute:wave:post'];
     assert.strictEqual(point.steps.length, 0,
       `execute:wave:post steps must be empty; got ${point.steps.length}`);
-    // #1143: claude-orchestration registers an execute:wave:post contribution
-    // providing the Workflow-tool backend guidance (default-off, claude-only).
-    assert.strictEqual(point.contributions.length, 3,
-      `execute:wave:post must have 3 contributions (claude-orchestration + external-job + mempalace); got ${point.contributions.length}`);
+    // #2285: claude-orchestration's dispatch-backend-selector contribution moved
+    // from execute:wave:post to execute:wave:pre — wave:post fires AFTER the
+    // wave already dispatched inline, too late to select a dispatch backend.
+    assert.strictEqual(point.contributions.length, 2,
+      `execute:wave:post must have 2 contributions (external-job + mempalace); got ${point.contributions.length}`);
     const capIds = point.contributions.map(c => c.capId).sort();
-    assert.deepStrictEqual(capIds, ['claude-orchestration', 'external-job', 'mempalace'],
-      `execute:wave:post contributions must be claude-orchestration + external-job + mempalace; got ${capIds.join(',')}`);
+    assert.deepStrictEqual(capIds, ['external-job', 'mempalace'],
+      `execute:wave:post contributions must be external-job + mempalace; got ${capIds.join(',')}`);
+  });
+
+  test('[happy] real registry: execute:wave:pre has 1 contribution (claude-orchestration dispatch-backend selector, #2285)', () => {
+    const point = realRegistry.byLoopPoint['execute:wave:pre'];
+    assert.strictEqual(point.steps.length, 0,
+      `execute:wave:pre steps must be empty; got ${point.steps.length}`);
+    assert.strictEqual(point.contributions.length, 1,
+      `execute:wave:pre must have 1 contribution (claude-orchestration); got ${point.contributions.length}`);
+    const capIds = point.contributions.map(c => c.capId).sort();
+    assert.deepStrictEqual(capIds, ['claude-orchestration'],
+      `execute:wave:pre contributions must be claude-orchestration; got ${capIds.join(',')}`);
   });
 
 });