feat(model-profiles): add adaptive preset with role-based model assignment (#1806)

Add a fourth model profile preset that assigns models by agent role:
opus for planning and debugging (reasoning-critical), sonnet for
execution and research (follows instructions), haiku for mapping and
checking (high volume, structured output).

This gives solo developers on paid API tiers a cost-effective middle
ground — quality where it matters most (planning) without overspending
on mechanical tasks (mapping, checking).

Per-agent overrides via model_overrides continue to take precedence
over any profile preset, including adaptive.

Closes #1713

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

tests/model-profiles.test.cjs

@@ -31,11 +31,12 @@ describe('MODEL_PROFILES', () => {
     }
   });
 
-  test('every agent has quality, balanced, and budget profiles', () => {
+  test('every agent has quality, balanced, budget, and adaptive profiles', () => {
     for (const [agent, profiles] of Object.entries(MODEL_PROFILES)) {
       assert.ok(profiles.quality, `${agent} missing quality profile`);
       assert.ok(profiles.balanced, `${agent} missing balanced profile`);
       assert.ok(profiles.budget, `${agent} missing budget profile`);
+      assert.ok(profiles.adaptive, `${agent} missing adaptive profile`);
     }
   });
 
@@ -65,7 +66,7 @@ describe('MODEL_PROFILES', () => {
 
 describe('VALID_PROFILES', () => {
   test('contains quality, balanced, and budget', () => {
-    assert.deepStrictEqual(VALID_PROFILES.sort(), ['balanced', 'budget', 'quality']);
+    assert.deepStrictEqual(VALID_PROFILES.sort(), ['adaptive', 'balanced', 'budget', 'quality']);
   });
 
   test('is derived from MODEL_PROFILES keys', () => {
@@ -96,6 +97,24 @@ describe('getAgentToModelMapForProfile', () => {
     assert.strictEqual(map['gsd-executor'], 'opus');
   });
 
+  test('returns correct models for adaptive profile', () => {
+    const map = getAgentToModelMapForProfile('adaptive');
+    assert.strictEqual(map['gsd-planner'], 'opus', 'planner should use opus in adaptive');
+    assert.strictEqual(map['gsd-debugger'], 'opus', 'debugger should use opus in adaptive');
+    assert.strictEqual(map['gsd-executor'], 'sonnet', 'executor should use sonnet in adaptive');
+    assert.strictEqual(map['gsd-codebase-mapper'], 'haiku', 'mapper should use haiku in adaptive');
+    assert.strictEqual(map['gsd-plan-checker'], 'haiku', 'checker should use haiku in adaptive');
+  });
+
+  test('resolution order: override > profile > default', () => {
+    // This tests the conceptual resolution — actual runtime test is in resolveModelInternal
+    const map = getAgentToModelMapForProfile('adaptive');
+    // Profile gives planner opus
+    assert.strictEqual(map['gsd-planner'], 'opus');
+    // An override would take precedence (tested via resolveModelInternal in model-alias-map tests)
+    // Default fallback is 'sonnet' (core.cjs line 1320)
+  });
+
   test('returns all agents in the map', () => {
     const map = getAgentToModelMapForProfile('balanced');
     const agentCount = Object.keys(MODEL_PROFILES).length;