✨ feat(query-editor): 新增选择当前语句快捷键

- 快捷键配置：新增选择当前语句动作，默认绑定 Ctrl+E
- 编辑器接入：在 Monaco 查询编辑器中注册选择当前语句 action
- 语句识别：新增 SQL 语句范围解析，支持按光标定位当前语句
- 兼容处理：忽略字符串、注释和 dollar quote 内的分号
- 测试覆盖：补充快捷键默认配置和语句选择解析单元测试
Refs #404

frontend/src/utils/sqlStatementSelection.ts

@@ -0,0 +1,159 @@
+export interface SqlStatementRange {
+  start: number;
+  end: number;
+  text: string;
+}
+
+const isWhitespace = (ch: string): boolean => (
+  ch === ' ' || ch === '\t' || ch === '\n' || ch === '\r'
+);
+
+const trimStatementRange = (sql: string, start: number, end: number): SqlStatementRange | null => {
+  let nextStart = Math.max(0, start);
+  let nextEnd = Math.min(sql.length, Math.max(start, end));
+
+  while (nextStart < nextEnd && isWhitespace(sql[nextStart])) {
+    nextStart++;
+  }
+  while (nextEnd > nextStart && isWhitespace(sql[nextEnd - 1])) {
+    nextEnd--;
+  }
+
+  if (nextStart >= nextEnd) {
+    return null;
+  }
+
+  return {
+    start: nextStart,
+    end: nextEnd,
+    text: sql.slice(nextStart, nextEnd),
+  };
+};
+
+export const findSqlStatementRanges = (sql: string): SqlStatementRange[] => {
+  const text = String(sql || '').replace(/\r\n/g, '\n');
+  const ranges: SqlStatementRange[] = [];
+
+  let statementStart = 0;
+  let inSingle = false;
+  let inDouble = false;
+  let inBacktick = false;
+  let escaped = false;
+  let inLineComment = false;
+  let inBlockComment = false;
+  let dollarTag: string | null = null;
+
+  const push = (end: number) => {
+    const range = trimStatementRange(text, statementStart, end);
+    if (range) {
+      ranges.push(range);
+    }
+  };
+
+  for (let index = 0; index < text.length; index++) {
+    const ch = text[index];
+    const next = index + 1 < text.length ? text[index + 1] : '';
+    const prev = index > 0 ? text[index - 1] : '';
+    const next2 = index + 2 < text.length ? text[index + 2] : '';
+
+    if (dollarTag) {
+      if (text.startsWith(dollarTag, index)) {
+        index += dollarTag.length - 1;
+        dollarTag = null;
+      }
+      continue;
+    }
+
+    if (inLineComment) {
+      if (ch === '\n') {
+        inLineComment = false;
+      }
+      continue;
+    }
+
+    if (inBlockComment) {
+      if (ch === '*' && next === '/') {
+        index++;
+        inBlockComment = false;
+      }
+      continue;
+    }
+
+    if (!inSingle && !inDouble && !inBacktick) {
+      if (ch === '/' && next === '*') {
+        index++;
+        inBlockComment = true;
+        continue;
+      }
+      if (ch === '#') {
+        inLineComment = true;
+        continue;
+      }
+      if (ch === '-' && next === '-' && (index === 0 || isWhitespace(prev)) && (next2 === '' || isWhitespace(next2))) {
+        index++;
+        inLineComment = true;
+        continue;
+      }
+      if (ch === '$') {
+        const match = text.slice(index).match(/^\$[A-Za-z0-9_]*\$/);
+        if (match?.[0]) {
+          dollarTag = match[0];
+          index += dollarTag.length - 1;
+          continue;
+        }
+      }
+    }
+
+    if (escaped) {
+      escaped = false;
+      continue;
+    }
+
+    if ((inSingle || inDouble) && ch === '\\') {
+      escaped = true;
+      continue;
+    }
+
+    if (!inDouble && !inBacktick && ch === "'") {
+      inSingle = !inSingle;
+      continue;
+    }
+    if (!inSingle && !inBacktick && ch === '"') {
+      inDouble = !inDouble;
+      continue;
+    }
+    if (!inSingle && !inDouble && ch === '`') {
+      inBacktick = !inBacktick;
+      continue;
+    }
+
+    if (!inSingle && !inDouble && !inBacktick && (ch === ';' || ch === '；')) {
+      push(index);
+      statementStart = index + 1;
+    }
+  }
+
+  push(text.length);
+  return ranges;
+};
+
+export const resolveCurrentSqlStatementRange = (sql: string, cursorOffset: number): SqlStatementRange | null => {
+  const text = String(sql || '').replace(/\r\n/g, '\n');
+  const offset = Math.max(0, Math.min(text.length, Number.isFinite(cursorOffset) ? cursorOffset : 0));
+  const ranges = findSqlStatementRanges(text);
+  if (ranges.length === 0) {
+    return null;
+  }
+
+  const containingRange = ranges.find((range) => offset >= range.start && offset <= range.end);
+  if (containingRange) {
+    return containingRange;
+  }
+
+  const nextRange = ranges.find((range) => offset < range.start);
+  if (nextRange) {
+    return nextRange;
+  }
+
+  return ranges[ranges.length - 1];
+};