fix: forward --exact flag to Playwright for role, label, and placeholder locators (#402) (#403)

Summary

- The `--exact` flag on `find role`, `find label`, and `find placeholder` was accepted by the CLI but silently dropped by the server. The Zod validation schema, TypeScript types, and action handlers all lacked the `exact` field, so it was stripped before reaching Playwright's `getByRole`, `getByLabel`, and `getByPlaceholder` calls.
- Added `exact` to the schema, types, and handler for all three locators so the flag is forwarded to Playwright as intended.
- Added tests confirming `exact: true` survives protocol parsing for `getbyrole`, `getbylabel`, and `getbyplaceholder`.

Fixes #402

src/actions.ts

@@ -887,7 +887,7 @@ async function handleGetByRole(
   browser: BrowserManager
 ): Promise<Response> {
   const page = browser.getPage();
-  const locator = page.getByRole(command.role as any, { name: command.name });
+  const locator = page.getByRole(command.role as any, { name: command.name, exact: command.exact });
 
   switch (command.subaction) {
     case 'click':
@@ -927,7 +927,7 @@ async function handleGetByLabel(
   browser: BrowserManager
 ): Promise<Response> {
   const page = browser.getPage();
-  const locator = page.getByLabel(command.label);
+  const locator = page.getByLabel(command.label, { exact: command.exact });
 
   switch (command.subaction) {
     case 'click':
@@ -947,7 +947,7 @@ async function handleGetByPlaceholder(
   browser: BrowserManager
 ): Promise<Response> {
   const page = browser.getPage();
-  const locator = page.getByPlaceholder(command.placeholder);
+  const locator = page.getByPlaceholder(command.placeholder, { exact: command.exact });
 
   switch (command.subaction) {
     case 'click':