feat: preferences dialog, SQL formatter, and enhanced table context menu

- PreferencesDialog (Tools → Preferences, Ctrl+,): font family/size,
  word wrap, default page size, query timeout, max history, auto-commit;
  font changes apply live to all open editors via apply_settings() cascade
- CodeEditor and TableViewer now read initial values from settings singleton
- SQL formatter (≡ Format button): uses sqlparse to reindent and uppercase
  keywords; gracefully prompts to install sqlparse if missing
- Table viewer context menu: "Filter by this value" (populates WHERE and
  reloads), "Copy row as SQL INSERT" (ready-to-paste INSERT statements),
  renamed "Copy row" → "Copy row as TSV" for clarity

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

app/ui/sql_editor.py

@@ -18,6 +18,7 @@ from app.ui.syntax_highlighter import SQLHighlighter
 from app.ui.results_panel import ResultsPanel
 from app.ui.sql_completer import SqlCompleter
 from app.utils.worker import QueryWorker
+from app.config.settings import get_settings
 
 
 # ── Line-number gutter ────────────────────────────────────────────────────────
@@ -42,11 +43,12 @@ class CodeEditor(QPlainTextEdit):
         self._line_area = LineNumberArea(self)
         self._completer: "SqlCompleter | None" = None
 
-        # Font
-        font = QFont("Consolas", 13)
-        font.setFixedPitch(True)
-        self.setFont(font)
-        self.setTabStopDistance(QFontMetrics(font).horizontalAdvance(" ") * 4)
+        self._apply_font()
+        self.setLineWrapMode(
+            QPlainTextEdit.LineWrapMode.WidgetWidth
+            if get_settings().get("word_wrap", False)
+            else QPlainTextEdit.LineWrapMode.NoWrap
+        )
 
         # Connect signals
         self.blockCountChanged.connect(self._update_line_area_width)
@@ -112,6 +114,22 @@ class CodeEditor(QPlainTextEdit):
             bottom = top + round(self.blockBoundingRect(block).height())
             number += 1
 
+    def _apply_font(self) -> None:
+        s = get_settings()
+        font = QFont(s.get("font_family", "Consolas"), s.get("font_size", 13))
+        font.setFixedPitch(True)
+        self.setFont(font)
+        self.setTabStopDistance(QFontMetrics(font).horizontalAdvance(" ") * 4)
+
+    def apply_settings(self) -> None:
+        """Re-read settings and apply font + word-wrap live."""
+        self._apply_font()
+        self.setLineWrapMode(
+            QPlainTextEdit.LineWrapMode.WidgetWidth
+            if get_settings().get("word_wrap", False)
+            else QPlainTextEdit.LineWrapMode.NoWrap
+        )
+
     def set_completer(self, completer: "SqlCompleter") -> None:
         self._completer = completer
 
@@ -430,6 +448,10 @@ class EditorTab(QWidget):
         self._explain_btn = QPushButton("🔎  Explain")
         self._explain_btn.clicked.connect(self._explain)
 
+        self._format_btn = QPushButton("≡  Format")
+        self._format_btn.setToolTip("Auto-format SQL  (requires sqlparse)")
+        self._format_btn.clicked.connect(self._format_sql)
+
         self._export_btn = QPushButton("📤  Export")
         self._export_btn.clicked.connect(self._export)
 
@@ -439,6 +461,7 @@ class EditorTab(QWidget):
         toolbar.addWidget(self._run_btn)
         toolbar.addWidget(self._stop_btn)
         toolbar.addWidget(self._explain_btn)
+        toolbar.addWidget(self._format_btn)
         toolbar.addWidget(self._export_btn)
         toolbar.addStretch()
         toolbar.addWidget(self._db_label)
@@ -523,6 +546,30 @@ class EditorTab(QWidget):
     def _export(self):
         self._results.export_dialog()
 
+    def _format_sql(self):
+        try:
+            import sqlparse
+        except ImportError:
+            QMessageBox.warning(
+                self, "Package Missing",
+                "SQL formatting requires sqlparse.\n\nInstall it with:\n  pip install sqlparse",
+            )
+            return
+        sql = self._editor.toPlainText().strip()
+        if not sql:
+            return
+        formatted = sqlparse.format(
+            sql,
+            reindent=True,
+            keyword_case="upper",
+            identifier_case="lower",
+            strip_comments=False,
+            use_space_around_operators=True,
+        )
+        cursor = self._editor.textCursor()
+        cursor.select(QTextCursor.SelectionType.Document)
+        cursor.insertText(formatted)
+
     def set_context(self, driver, database: str) -> None:
         """Update driver/database and refresh schema completions."""
         self._driver   = driver
@@ -558,6 +605,9 @@ class EditorTab(QWidget):
     def get_sql(self) -> str:
         return self._editor.toPlainText()
 
+    def apply_settings(self) -> None:
+        self._editor.apply_settings()
+
 
 # ── Tabbed SQL editor container ───────────────────────────────────────────────
 
@@ -651,6 +701,12 @@ class SQLEditorWidget(QWidget):
         w = self._tabs.currentWidget()
         return w if isinstance(w, EditorTab) else None
 
+    def apply_settings(self) -> None:
+        for i in range(self._tabs.count()):
+            tab = self._tabs.widget(i)
+            if isinstance(tab, EditorTab):
+                tab.apply_settings()
+
     def open_sql_for(self, driver, database: str, sql: str = ""):
         tab = self.new_tab(driver, database, sql,
                            title=f"SQL — {database}")