fix(tools/sqlite): reject comments, terminators, and pagination keywords in where=

The structured SQLite helper interpolates `where=` directly into SQL.
A crafted clause like `where=1=1 LIMIT 1000000 --` could comment out
the helper's bound `LIMIT ? OFFSET ?`, returning the full table in
violation of the documented pagination contract.

Validate where= at the selector boundary and reject SQL comments,
statement terminators, and pagination/attach/pragma keywords. Raw SQL
remains available via ?q=SELECT... for callers that need it.

Fixes #735

packages/coding-agent/test/tools/sqlite.test.ts

@@ -288,6 +288,18 @@ describe("SQLite tool support", () => {
 		expect(text).not.toContain("Bob");
 	});
 
+	it("rejects where= clauses that try to bypass pagination", () => {
+		expect(() => parseSqliteSelector("users", "where=1=1 LIMIT 1000000 --&limit=2&offset=0")).toThrow(
+			/comments or statement terminators/i,
+		);
+		expect(() => parseSqliteSelector("users", "where=status='active' LIMIT 1")).toThrow(
+			/LIMIT\/OFFSET\/UNION/i,
+		);
+		expect(() => parseSqliteSelector("users", "where=1=1; DROP TABLE users")).toThrow(
+			/comments or statement terminators/i,
+		);
+	});
+
 	it("executes raw read-only SQL queries", async () => {
 		const result = await readTool.execute("sqlite-raw-query", {
 			path: `${sqlitePath}?q=SELECT+name+FROM+users+ORDER+BY+id+LIMIT+2`,