fix(#3936): dispatch quick research with researcher persona and model (#4158)

* test(#3936): quick research dispatch must use researcher persona/model

Regression tests for the planner-persona leak in quick's Step 4.75
research dispatch: init quick emits researcher_model, the workflow
resolves AGENT_SKILLS_RESEARCHER and parses researcher_model, and the
researcher dispatch uses the researcher persona/tier while planner and
executor dispatches keep their own.

* fix(#3936): dispatch quick research with researcher persona and model

cmdInitQuick now emits researcher_model (parity with the plan-phase
init), quick.md resolves AGENT_SKILLS_RESEARCHER and parses the new
field, and Step 4.75's dispatch swaps ${AGENT_SKILLS_PLANNER}/
{planner_model} for the researcher's own persona and tier. The #2517
model-omission list gains researcher_model.

Emitted-Drift-Ack-Growth: quick.md — researcher persona resolution line + researcher_model parse-list entry (#3936)

* chore(#3936): backfill changeset pr number

---------

Co-authored-by: sim <sim@local>

src/init.cts

@@ -1467,6 +1467,10 @@ function cmdInitQuick(
     executor_model: resolveModelInternal(cwd, 'gsd-executor'),
     checker_model: resolveModelInternal(cwd, 'gsd-plan-checker'),
     verifier_model: resolveModelInternal(cwd, 'gsd-verifier'),
+    // #3936: Step 4.75 dispatches gsd-phase-researcher; resolve its own tier
+    // (parity with cmdInitPlanPhase) so the research spawn stops pinning
+    // planner_model.
+    researcher_model: resolveModelInternal(cwd, 'gsd-phase-researcher'),
     // #2072: the quick review step spawns gsd-code-reviewer; resolve its own model
     // so model_overrides / models.verification apply (was reusing executor_model).
     reviewer_model: resolveModelInternal(cwd, 'gsd-code-reviewer'),