feat: design system overhaul — sidebar, AI chats, settings, brainstorm, color cleanup

- Sidebar: dynamic brand-accent colors, brainstorm section restyled
- AI chat general: popup panel with expand/collapse, hides when contextual AI open
- AI chat contextual: tabs reordered (Actions first), X close button, height fix
- Settings: all tabs restyled, 6 new color presets (sage, terracotta, iron, etc.)
- Global color cleanup: emerald/orange hardcoded → brand-accent dynamic
- Brainstorm page: orange → brand-accent throughout
- PageEntry animation component added to key pages
- Floating AI button: bg-brand-accent instead of hardcoded black
- i18n: all 15 locales updated with new AI/billing keys
- Billing: freemium quota tracking, BYOK, stripe subscription scaffolding
- Admin: integrated into new design
- AGENTS.md + CLAUDE.md project rules added

.agent/skills/suno-band-profile-manager/scripts/tests/test-diff-profiles.py

@@ -0,0 +1,133 @@
+#!/usr/bin/env python3
+# /// script
+# requires-python = ">=3.10"
+# dependencies = ["pytest>=7.0", "pyyaml>=6.0"]
+# ///
+"""Tests for diff-profiles.py"""
+
+import sys
+from pathlib import Path
+
+import pytest
+import yaml
+
+sys.path.insert(0, str(Path(__file__).parent.parent))
+from importlib.util import spec_from_file_location, module_from_spec
+
+spec = spec_from_file_location(
+    "diff_profiles",
+    Path(__file__).parent.parent / "diff-profiles.py"
+)
+diff_profiles_mod = module_from_spec(spec)
+spec.loader.exec_module(diff_profiles_mod)
+diff_profiles = diff_profiles_mod.diff_profiles
+
+
+PROFILE_A = {
+    "name": "Test Band",
+    "genre": "indie rock",
+    "mood": "melancholic",
+    "model_preference": "v4.5-all",
+    "tier": "free",
+    "style_baseline": "Indie rock with warm guitars",
+    "vocal": {
+        "gender": "male",
+        "tone": "warm",
+        "delivery": "intimate",
+        "energy": "restrained",
+    },
+}
+
+
+def write_yaml(tmp_path, filename, data):
+    path = tmp_path / filename
+    with open(path, "w") as f:
+        yaml.dump(data, f)
+    return path
+
+
+def test_identical_profiles(tmp_path):
+    a = write_yaml(tmp_path, "a.yaml", PROFILE_A)
+    b = write_yaml(tmp_path, "b.yaml", PROFILE_A)
+    result = diff_profiles(a, b)
+    assert result["status"] == "pass"
+    assert result["has_changes"] is False
+    assert result["summary"]["total_changes"] == 0
+
+
+def test_changed_fields(tmp_path):
+    modified = {**PROFILE_A, "genre": "electronic", "mood": "energetic"}
+    a = write_yaml(tmp_path, "a.yaml", PROFILE_A)
+    b = write_yaml(tmp_path, "b.yaml", modified)
+    result = diff_profiles(a, b)
+    assert result["has_changes"] is True
+    assert result["summary"]["fields_changed"] == 2
+    changed_fields = [c["field"] for c in result["changed"]]
+    assert "genre" in changed_fields
+    assert "mood" in changed_fields
+
+
+def test_added_fields(tmp_path):
+    modified = {**PROFILE_A, "language": "Spanish", "instrumental": True}
+    a = write_yaml(tmp_path, "a.yaml", PROFILE_A)
+    b = write_yaml(tmp_path, "b.yaml", modified)
+    result = diff_profiles(a, b)
+    assert result["has_changes"] is True
+    assert result["summary"]["fields_added"] >= 2
+    added_fields = [c["field"] for c in result["added"]]
+    assert "language" in added_fields
+    assert "instrumental" in added_fields
+
+
+def test_removed_fields(tmp_path):
+    modified = {k: v for k, v in PROFILE_A.items() if k != "mood"}
+    a = write_yaml(tmp_path, "a.yaml", PROFILE_A)
+    b = write_yaml(tmp_path, "b.yaml", modified)
+    result = diff_profiles(a, b)
+    assert result["has_changes"] is True
+    assert result["summary"]["fields_removed"] >= 1
+    removed_fields = [c["field"] for c in result["removed"]]
+    assert "mood" in removed_fields
+
+
+def test_nested_changes(tmp_path):
+    modified = {**PROFILE_A, "vocal": {**PROFILE_A["vocal"], "tone": "bright, clear"}}
+    a = write_yaml(tmp_path, "a.yaml", PROFILE_A)
+    b = write_yaml(tmp_path, "b.yaml", modified)
+    result = diff_profiles(a, b)
+    assert result["has_changes"] is True
+    changed_fields = [c["field"] for c in result["changed"]]
+    assert "vocal.tone" in changed_fields
+
+
+def test_missing_original(tmp_path):
+    b = write_yaml(tmp_path, "b.yaml", PROFILE_A)
+    result = diff_profiles(tmp_path / "nope.yaml", b)
+    assert result["status"] == "fail"
+    assert "errors" in result
+
+
+def test_missing_modified(tmp_path):
+    a = write_yaml(tmp_path, "a.yaml", PROFILE_A)
+    result = diff_profiles(a, tmp_path / "nope.yaml")
+    assert result["status"] == "fail"
+
+
+def test_invalid_yaml(tmp_path):
+    a = write_yaml(tmp_path, "a.yaml", PROFILE_A)
+    bad = tmp_path / "bad.yaml"
+    bad.write_text(": {{invalid yaml")
+    result = diff_profiles(a, bad)
+    assert result["status"] == "fail"
+
+
+def test_mixed_changes(tmp_path):
+    modified = {**PROFILE_A, "genre": "electronic", "language": "French"}
+    del modified["mood"]
+    a = write_yaml(tmp_path, "a.yaml", PROFILE_A)
+    b = write_yaml(tmp_path, "b.yaml", modified)
+    result = diff_profiles(a, b)
+    assert result["has_changes"] is True
+    assert result["summary"]["fields_changed"] >= 1
+    assert result["summary"]["fields_added"] >= 1
+    assert result["summary"]["fields_removed"] >= 1