polish: row numbers, ping indicator, frozen column, keyboard nav

- ResultsPanel: _RowNumberProxy keeps vertical header numbers sequential
  in visual order (sort-stable); both views get a 48 px wide row-number header
- MainWindow: _PingWorker pings each active connection every 30 s via
  test_connection(); status dot (green/red) shown in status bar with tooltip
- TableViewer: 📌 toggle freezes first column using dual-view overlay
  (_frozen_view child widget) with synced scroll, row heights, and resize
  event-filter; column 0 is hidden in the main view while frozen
- RowDialog: OK set as default button; first field focused on open
- ConnectionDialog: OK set as default; Enter in password field submits

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

CLAUDE.md

@@ -140,6 +140,10 @@ All four drivers have a `_where(where: dict) → (clause_str, params)` static he
 - File open/save/recent: Ctrl+O open SQL file, Ctrl+S save, File → Open Recent (persisted to `~/.dbclient/recent_files.json`, max 10)
 - Ctrl+W to close current workspace tab
 - Catppuccin Frappé theme: full palette upgrade from Mocha; all colors updated in `resources/style.qss`, syntax highlighter, completer popup, and inline Python stylesheets
+- Row numbers column in results grid: `_RowNumberProxy` shows sequential visual-order numbers in the vertical header (sort-stable); fixed 48 px wide header in both `ResultsPanel` and `TableViewer`
+- Connection ping indicator: 30-second `_PingWorker` (QThread) pings each active connection via `test_connection()`; status dot (● green / ● red) shown in status bar right side with per-connection tooltip
+- Frozen first column in `TableViewer`: 📌 toggle button in toolbar; dual-view overlay (`_frozen_view` child of `_table_view`) with synced vertical scroll and row heights; event-filter updates geometry on resize
+- Keyboard navigation in dialogs: OK set as default button (Enter submits) in `RowDialog` and `ConnectionDialog`; focus jumps to first input field on open; Enter in password field submits `ConnectionDialog`
 
 ### Not Yet Implemented
 **High impact:**
@@ -153,9 +157,3 @@ All four drivers have a `_where(where: dict) → (clause_str, params)` static he
 - Global schema search: search across all tables/columns/procedures in a database
 - Light theme: Catppuccin Latte or similar, toggle from Preferences
 - Schema diff: compare two database schemas and show structural differences
-
-**Small polish:**
-- Row numbers column in results grid (virtual, not from DB)
-- Connection ping indicator: periodic heartbeat dot in tab / status bar
-- Frozen / pinned columns in table viewer (keep PK column always visible while scrolling)
-- Keyboard navigation in RowDialog / connection dialogs (Tab order, Enter to confirm)

app/main_window.py

@@ -15,7 +15,7 @@ from PyQt6.QtWidgets import (
     QTabWidget, QStatusBar, QLabel, QMessageBox, QDockWidget,
     QPushButton, QApplication, QMenu, QInputDialog, QFileDialog,
 )
-from PyQt6.QtCore import Qt, QTimer
+from PyQt6.QtCore import Qt, QTimer, QThread, pyqtSignal
 from PyQt6.QtGui import QAction, QColor, QKeySequence
 
 from app.ui.schema_browser    import SchemaBrowser
@@ -41,6 +41,23 @@ from app.utils.logger import get_logger
 _log = get_logger(__name__)
 
 
+class _PingWorker(QThread):
+    """Background thread that pings one connection and emits the result."""
+    pinged = pyqtSignal(str, bool)   # (profile_id, ok)
+
+    def __init__(self, pid: str, driver, parent=None):
+        super().__init__(parent)
+        self._pid    = pid
+        self._driver = driver
+
+    def run(self):
+        try:
+            ok, _ = self._driver.test_connection()
+            self.pinged.emit(self._pid, ok)
+        except Exception:
+            self.pinged.emit(self._pid, False)
+
+
 class MainWindow(QMainWindow):
 
     def __init__(self):
@@ -53,11 +70,19 @@ class MainWindow(QMainWindow):
         self._active_drivers: dict = {}
         # profile_id → ConnectionProfile  (all loaded profiles, connected or not)
         self._all_profiles:   dict = {}
+        # ping state
+        self._ping_results: dict = {}   # profile_id → bool
+        self._ping_workers: list = []   # keep QThread refs alive
 
         self._build_ui()
         self._build_menus()
         self._build_status_bar()
 
+        # Periodic connection heartbeat (every 30 s)
+        self._ping_timer = QTimer(self)
+        self._ping_timer.timeout.connect(self._ping_all_connections)
+        self._ping_timer.start(30_000)
+
         # Load saved profiles after the window is shown
         QTimer.singleShot(0, self._load_saved_profiles)
 
@@ -234,6 +259,12 @@ class MainWindow(QMainWindow):
         self._conn_lbl.setMinimumWidth(160)
         sb.addPermanentWidget(self._conn_lbl)
 
+        self._ping_lbl = QLabel("")
+        self._ping_lbl.setFixedWidth(16)
+        self._ping_lbl.setAlignment(Qt.AlignmentFlag.AlignCenter)
+        self._ping_lbl.setToolTip("Connection heartbeat")
+        sb.addPermanentWidget(self._ping_lbl)
+
     def _set_status(self, msg: str):
         self._status_lbl.setText(msg)
 
@@ -404,6 +435,7 @@ class MainWindow(QMainWindow):
         else:
             self._schema_browser.remove_connection(profile_id, keep_saved=False)
         self._all_profiles.pop(profile_id, None)
+        self._ping_results.pop(profile_id, None)
         delete_profile(profile_id)
         self._set_status(f"Connection '{profile.name}' deleted.")
 
@@ -484,6 +516,44 @@ class MainWindow(QMainWindow):
             preview = value[:60] + ("…" if len(value) > 60 else "")
             self._cell_lbl.setText(f"  {preview}")
 
+    # ── Connection heartbeat ──────────────────────────────────────────────────
+
+    def _ping_all_connections(self):
+        # Drop finished workers
+        self._ping_workers = [w for w in self._ping_workers if w.isRunning()]
+        if not self._active_drivers:
+            self._ping_lbl.setText("")
+            return
+        for pid, driver in list(self._active_drivers.items()):
+            # Skip if a ping for this connection is already in flight
+            if any(getattr(w, "_pid", None) == pid for w in self._ping_workers):
+                continue
+            worker = _PingWorker(pid, driver)
+            worker.pinged.connect(self._on_ping_result)
+            worker.start()
+            self._ping_workers.append(worker)
+
+    def _on_ping_result(self, pid: str, ok: bool):
+        if pid not in self._active_drivers:
+            return
+        self._ping_results[pid] = ok
+        all_ok = all(self._ping_results.get(p, True) for p in self._active_drivers)
+        color = "#a6d189" if all_ok else "#e78284"
+        self._ping_lbl.setText("●")
+        self._ping_lbl.setStyleSheet(f"color: {color}; font-size: 11pt;")
+        lines = []
+        for p_id in self._active_drivers:
+            profile = self._all_profiles.get(p_id)
+            name = profile.name if profile else p_id
+            icon = "✅" if self._ping_results.get(p_id, True) else "❌"
+            lines.append(f"{icon} {name}")
+        self._ping_lbl.setToolTip("Connections:\n" + "\n".join(lines))
+        if not ok:
+            profile = self._all_profiles.get(pid)
+            name = profile.name if profile else pid
+            _log.warning("Heartbeat failed for '%s'", name)
+            self._set_status(f"⚠️  Connection heartbeat failed: {name}")
+
     # ── File open / save ──────────────────────────────────────────────────────
 
     def _open_sql_file(self, filepath: str = None):

app/ui/connection_dialog.py

@@ -88,6 +88,9 @@ class ConnectionDialog(QDialog):
         )
         bbox.accepted.connect(self._accept)
         bbox.rejected.connect(self.reject)
+        ok_btn = bbox.button(QDialogButtonBox.StandardButton.Ok)
+        if ok_btn:
+            ok_btn.setDefault(True)
 
         btn_row = QHBoxLayout()
         btn_row.addWidget(self._test_btn)
@@ -167,6 +170,12 @@ class ConnectionDialog(QDialog):
         self._timeout.setSuffix(" sec")
         form.addRow("Timeout:", self._timeout)
 
+        # Enter in password submits the dialog
+        self._password.returnPressed.connect(self._accept)
+
+        # Focus starts on the name field
+        self._name.setFocus()
+
         return w
 
     def _build_ssl_tab(self) -> QWidget:

app/ui/results_panel.py

@@ -19,6 +19,14 @@ from PyQt6.QtGui import QColor, QFont
 from app.models.result_table_model import ResultTableModel
 
 
+class _RowNumberProxy(QSortFilterProxyModel):
+    """Proxy that shows sequential visual-order row numbers in the vertical header."""
+    def headerData(self, section, orientation, role=Qt.ItemDataRole.DisplayRole):
+        if orientation == Qt.Orientation.Vertical and role == Qt.ItemDataRole.DisplayRole:
+            return str(section + 1)
+        return super().headerData(section, orientation, role)
+
+
 class ResultsPanel(QWidget):
     status_message = pyqtSignal(str)
 
@@ -86,7 +94,7 @@ class ResultsPanel(QWidget):
     def _make_table_tab(self, cols: list, rows: list) -> tuple:
         model = ResultTableModel()
         model.set_data(cols, rows)
-        proxy = QSortFilterProxyModel()
+        proxy = _RowNumberProxy()
         proxy.setSourceModel(model)
 
         table = QTableView()
@@ -99,6 +107,7 @@ class ResultsPanel(QWidget):
             QHeaderView.ResizeMode.Interactive)
         table.horizontalHeader().setStretchLastSection(True)
         table.verticalHeader().setDefaultSectionSize(24)
+        table.verticalHeader().setFixedWidth(48)
         table.setContextMenuPolicy(Qt.ContextMenuPolicy.CustomContextMenu)
         table.customContextMenuRequested.connect(
             lambda pos, t=table, p=proxy, m=model:

app/ui/table_viewer.py

@@ -16,7 +16,7 @@ from PyQt6.QtWidgets import (
     QMenu, QApplication,
 )
 from PyQt6.QtCore import (
-    Qt, QAbstractTableModel, QModelIndex, pyqtSignal,
+    Qt, QAbstractTableModel, QModelIndex, pyqtSignal, QEvent,
 )
 from PyQt6.QtGui import QColor, QBrush, QFont, QKeySequence, QShortcut
 
@@ -267,8 +267,15 @@ class RowDialog(QDialog):
         )
         bbox.accepted.connect(self.accept)
         bbox.rejected.connect(self.reject)
+        ok_btn = bbox.button(QDialogButtonBox.StandardButton.Ok)
+        if ok_btn:
+            ok_btn.setDefault(True)
         root.addWidget(bbox)
 
+        # Focus the first input field so the user can start typing immediately
+        if self._fields:
+            next(iter(self._fields.values())).setFocus()
+
     @property
     def values(self) -> dict:
         """Return {col: value_or_None} for all fields.
@@ -380,6 +387,13 @@ class TableViewer(QWidget):
         tb.addWidget(self._edit_btn)
         tb.addWidget(self._delete_btn)
         tb.addStretch()
+
+        self._freeze_btn = QPushButton("📌")
+        self._freeze_btn.setFixedWidth(34)
+        self._freeze_btn.setToolTip("Freeze first column (keep it visible while scrolling)")
+        self._freeze_btn.setCheckable(True)
+        self._freeze_btn.clicked.connect(self._toggle_freeze)
+        tb.addWidget(self._freeze_btn)
         root.addLayout(tb)
 
         # ── Table view ─────────────────────────────────────────────────────────
@@ -395,6 +409,7 @@ class TableViewer(QWidget):
             QHeaderView.ResizeMode.Interactive)
         self._table_view.horizontalHeader().setStretchLastSection(True)
         self._table_view.verticalHeader().setDefaultSectionSize(24)
+        self._table_view.verticalHeader().setFixedWidth(48)
         self._table_view.setContextMenuPolicy(
             Qt.ContextMenuPolicy.CustomContextMenu)
         self._table_view.customContextMenuRequested.connect(self._context_menu)
@@ -415,6 +430,40 @@ class TableViewer(QWidget):
                   self._delete_selected)
         QShortcut(QKeySequence("Ins"), self._table_view, self._add_row)
 
+        # ── Frozen first-column overlay ───────────────────────────────────────
+        self._freeze_active = False
+        self._frozen_view = QTableView(self._table_view)
+        self._frozen_view.setModel(self._model)
+        self._frozen_view.setFocusPolicy(Qt.FocusPolicy.NoFocus)
+        self._frozen_view.setVerticalScrollBarPolicy(
+            Qt.ScrollBarPolicy.ScrollBarAlwaysOff)
+        self._frozen_view.setHorizontalScrollBarPolicy(
+            Qt.ScrollBarPolicy.ScrollBarAlwaysOff)
+        self._frozen_view.setAlternatingRowColors(True)
+        self._frozen_view.verticalHeader().hide()
+        self._frozen_view.horizontalHeader().setSectionResizeMode(
+            QHeaderView.ResizeMode.Fixed)
+        self._frozen_view.setStyleSheet(
+            "QTableView { border: none; border-right: 2px solid #8caaee; }")
+        self._frozen_view.hide()
+
+        # Sync vertical scroll between the two views
+        self._table_view.verticalScrollBar().valueChanged.connect(
+            self._frozen_view.verticalScrollBar().setValue)
+        self._frozen_view.verticalScrollBar().valueChanged.connect(
+            self._table_view.verticalScrollBar().setValue)
+
+        # Sync row heights
+        self._table_view.verticalHeader().sectionResized.connect(
+            lambda row, _, h: self._frozen_view.setRowHeight(row, h))
+
+        # Update frozen geometry when column 0 is resized
+        self._table_view.horizontalHeader().sectionResized.connect(
+            lambda col, _old, _new: self._update_frozen_geometry() if col == 0 else None)
+
+        # Event filter to handle main view resize
+        self._table_view.installEventFilter(self)
+
         root.addWidget(self._table_view, 1)
 
         # ── Pagination bar (prominent, always visible) ─────────────────────────
@@ -505,11 +554,58 @@ class TableViewer(QWidget):
         self._refresh_action_states()
         self._table_view.resizeColumnsToContents()
         self._table_view.horizontalHeader().setStretchLastSection(True)
+        if self._freeze_active and self._model.columnCount() > 0:
+            self._apply_freeze()
 
     def _on_error(self, msg: str):
         self._total_lbl.setText(f"Error: {msg[:80]}")
         self.status_message.emit(f"Error: {msg}")
 
+    # ── Frozen column ──────────────────────────────────────────────────────────
+
+    def _toggle_freeze(self, checked: bool):
+        self._freeze_active = checked
+        if checked and self._model.columnCount() > 0:
+            self._apply_freeze()
+        elif not checked:
+            self._unapply_freeze()
+
+    def _apply_freeze(self):
+        col_count = self._model.columnCount()
+        if col_count == 0:
+            return
+        self._frozen_view.setSelectionModel(self._table_view.selectionModel())
+        for c in range(col_count):
+            self._frozen_view.setColumnHidden(c, c != 0)
+        self._frozen_view.resizeColumnToContents(0)
+        self._table_view.setColumnHidden(0, True)
+        self._update_frozen_geometry()
+        self._frozen_view.show()
+        self._frozen_view.raise_()
+
+    def _unapply_freeze(self):
+        self._frozen_view.hide()
+        if self._model.columnCount() > 0:
+            self._table_view.setColumnHidden(0, False)
+
+    def _update_frozen_geometry(self):
+        if not self._freeze_active:
+            return
+        fw     = self._table_view.frameWidth()
+        vh_w   = self._table_view.verticalHeader().width()
+        col0_w = self._frozen_view.columnWidth(0)
+        self._frozen_view.setGeometry(
+            fw + vh_w,
+            fw,
+            col0_w,
+            self._table_view.height() - 2 * fw,
+        )
+
+    def eventFilter(self, obj, event):
+        if obj is self._table_view and event.type() == QEvent.Type.Resize:
+            self._update_frozen_geometry()
+        return False
+
     def _refresh_pagination(self):
         ps = self._page_size if self._page_size > 0 else max(self._total, 1)
         rows_loaded   = self._model.rowCount()