feat: split view multi-panneaux (#75) — PaneManager intégré avec split right/down, menu contextuel, raccourcis clavier, CSS responsive et tests

- PaneManager: splitRight/splitDown avec 1-4 panneaux, persistance localStorage, resize
- Viewer/TabManager pane-aware: fonctions getContentArea/getTabBar/getTabList
- Menu contextuel onglets: actions Diviser à droite / Diviser en bas / Fermer le panneau
- Raccourcis clavier: Ctrl+Alt+\ (split right), Ctrl+Alt+Shift+\ (split down), Ctrl+Alt+W (fermer panneau)
- CSS pane-grid: grille, poignées resize, bordure active pane, responsive (désactivé <768px)
- Tests: 22 nouveaux tests unitaires + régression (307 total, 100% green)
- Déployé sur Docker test (localhost:2021)

tests/test_pane_manager.py

@@ -0,0 +1,194 @@
+"""
+Tests for the Multi-Pane Split View (#75).
+
+Since PaneManager is a frontend JS module, these tests verify:
+  1. Backend integration: all file/sidebar/vault APIs still work (no regression)
+  2. Static file serving: pane-manager.js is served correctly
+  3. CSS: style.css includes pane grid classes
+  4. HTML: index.html includes the content-wrapper structure needed for panes
+"""
+import pytest
+import re
+from pathlib import Path
+
+PROJECT_ROOT = Path(__file__).resolve().parent.parent
+
+
+class TestPaneManagerStaticAssets:
+    """Verify pane-manager.js, style.css, and index.html are properly structured."""
+
+    def test_pane_manager_js_exists(self):
+        """PaneManager module file is present."""
+        path = PROJECT_ROOT / "frontend" / "js" / "pane-manager.js"
+        assert path.exists(), f"pane-manager.js not found at {path}"
+
+    def test_pane_manager_js_exports(self):
+        """PaneManager exports the expected API."""
+        path = PROJECT_ROOT / "frontend" / "js" / "pane-manager.js"
+        content = path.read_text()
+        assert "export default PaneManager" in content
+        assert "window.PaneManager = PaneManager" in content
+
+    def test_pane_manager_has_split_methods(self):
+        """PaneManager has splitRight and splitDown methods."""
+        path = PROJECT_ROOT / "frontend" / "js" / "pane-manager.js"
+        content = path.read_text()
+        assert "splitRight()" in content
+        assert "splitDown()" in content
+        assert "closePane(" in content
+        assert "closeActivePane()" in content
+        assert "isSplit()" in content
+        assert "getActiveContentArea()" in content
+
+    def test_pane_manager_has_keyboard_shortcuts(self):
+        """Keyboard shortcuts are registered."""
+        path = PROJECT_ROOT / "frontend" / "js" / "pane-manager.js"
+        content = path.read_text()
+        assert "ctrlKey" in content
+        assert '"\\\\"' in content or "'\\\\'" in content  # backslash key
+
+    def test_style_css_has_pane_grid_classes(self):
+        """style.css includes pane grid CSS classes."""
+        path = PROJECT_ROOT / "frontend" / "style.css"
+        content = path.read_text()
+        assert ".pane-grid" in content
+        assert ".pane-container" in content
+        assert ".pane-resize-handle" in content
+        assert ".pane-active" in content
+
+    def test_style_css_has_responsive_split(self):
+        """Responsive rules disable split below 768px."""
+        path = PROJECT_ROOT / "frontend" / "style.css"
+        content = path.read_text()
+        assert "@media (max-width: 768px)" in content
+        assert ".pane-grid" in content
+
+    def test_viewer_uses_pane_aware_helper(self):
+        """viewer.js has getContentArea() helper and uses it."""
+        path = PROJECT_ROOT / "frontend" / "js" / "viewer.js"
+        content = path.read_text()
+        assert "function getContentArea()" in content
+        assert "window.PaneManager" in content
+        # Should NOT have direct document.getElementById("content-area") except in fallback
+        direct_refs = [l for l in content.split("\n")
+                       if 'document.getElementById("content-area")' in l
+                       and "fallback" not in l.lower()]
+        # Only the fallback inside getContentArea should remain
+        assert len(direct_refs) <= 2, f"Too many direct content-area refs: {direct_refs}"
+
+    def test_ui_tab_manager_has_pane_helpers(self):
+        """TabManager in ui.js has _getContentArea, _getTabBar, _getTabList."""
+        path = PROJECT_ROOT / "frontend" / "js" / "ui.js"
+        content = path.read_text()
+        assert "_getContentArea()" in content
+        assert "_getTabBar()" in content
+        assert "_getTabList()" in content
+        assert "activatePaneTab(" in content
+
+    def test_ui_context_menu_has_split_actions(self):
+        """Tab context menu includes 'Diviser à droite' and 'Diviser en bas'."""
+        path = PROJECT_ROOT / "frontend" / "js" / "ui.js"
+        content = path.read_text()
+        assert "Diviser à droite" in content
+        assert "Diviser en bas" in content
+        assert "Fermer le panneau" in content
+        assert 'data-action="splitRight"' in content
+        assert 'data-action="splitDown"' in content
+
+    def test_html_has_content_wrapper(self):
+        """index.html has the content-wrapper structure needed for panes."""
+        path = PROJECT_ROOT / "frontend" / "index.html"
+        content = path.read_text()
+        assert 'class="content-wrapper"' in content
+        assert 'id="content-area"' in content
+        assert 'id="tab-bar"' in content
+        assert 'id="tab-list"' in content
+
+    def test_html_uses_es_modules(self):
+        """index.html uses ES module scripts for the frontend modules."""
+        path = PROJECT_ROOT / "frontend" / "index.html"
+        content = path.read_text()
+        # Should load the ES module app.js orchestrator
+        assert 'type="module"' in content
+
+    def test_brace_balance_pane_manager(self):
+        """PaneManager JS has balanced braces, parens, brackets."""
+        path = PROJECT_ROOT / "frontend" / "js" / "pane-manager.js"
+        content = path.read_text()
+        for char, name in [("{", "braces"), ("(", "parens"), ("[", "brackets")]:
+            close_map = {"{": "}", "(": ")", "[": "]"}
+            assert content.count(char) == content.count(close_map[char]), \
+                f"Unbalanced {name}: {content.count(char)} opens vs {content.count(close_map[char])} closes"
+
+    def test_brace_balance_viewer(self):
+        """viewer.js has balanced braces, parens, brackets."""
+        path = PROJECT_ROOT / "frontend" / "js" / "viewer.js"
+        content = path.read_text()
+        for char, name in [("{", "braces"), ("(", "parens"), ("[", "brackets")]:
+            close_map = {"{": "}", "(": ")", "[": "]"}
+            assert content.count(char) == content.count(close_map[char]), \
+                f"Unbalanced {name}: {content.count(char)} opens vs {content.count(close_map[char])} closes"
+
+    def test_brace_balance_ui(self):
+        """ui.js has balanced braces, parens, brackets."""
+        path = PROJECT_ROOT / "frontend" / "js" / "ui.js"
+        content = path.read_text()
+        for char, name in [("{", "braces"), ("(", "parens"), ("[", "brackets")]:
+            close_map = {"{": "}", "(": ")", "[": "]"}
+            assert content.count(char) == content.count(close_map[char]), \
+                f"Unbalanced {name}: {content.count(char)} opens vs {content.count(close_map[char])} closes"
+
+
+class TestBackendRegression:
+    """Verify backend APIs still work with frontend changes."""
+
+    def test_file_view_endpoint(self, client):
+        """GET /api/file/{vault} still returns expected fields."""
+        resp = client.get("/api/file/TestVault", params={"path": "note1.md"})
+        assert resp.status_code == 200
+        data = resp.json()
+        assert "title" in data or "path" in data
+
+    def test_vault_list_endpoint(self, client):
+        """GET /api/vaults still works."""
+        resp = client.get("/api/vaults")
+        assert resp.status_code == 200
+        data = resp.json()
+        assert isinstance(data, list)
+
+    def test_search_endpoint(self, client):
+        """GET /api/search still works."""
+        resp = client.get("/api/search?q=test")
+        assert resp.status_code == 200
+        data = resp.json()
+        assert "results" in data
+
+    def test_sidebar_tree_endpoint(self, client):
+        """GET /api/sidebar/tree/{vault} still works."""
+        resp = client.get("/api/sidebar/tree/vault1")
+        assert resp.status_code == 200
+
+    def test_static_css_served(self, client):
+        """style.css is served correctly."""
+        resp = client.get("/static/style.css")
+        assert resp.status_code == 200
+        assert "text/css" in resp.headers.get("content-type", "")
+
+    def test_static_js_served(self, client):
+        """app.js (ES module) is served correctly."""
+        resp = client.get("/static/js/app.js")
+        assert resp.status_code == 200
+        assert "javascript" in resp.headers.get("content-type", "").lower()
+
+    def test_pane_manager_js_served(self, client):
+        """pane-manager.js is served as static asset."""
+        resp = client.get("/static/js/pane-manager.js")
+        assert resp.status_code == 200
+        assert "javascript" in resp.headers.get("content-type", "").lower()
+        assert "PaneManager" in resp.text
+
+    def test_index_html_served(self, client):
+        """index.html is served and contains content-wrapper."""
+        resp = client.get("/")
+        # May redirect or return 200 depending on auth
+        assert resp.status_code in (200, 302, 401)