fixup! fix(imap): detect iMIP when method= is missing or mime is application/ics

Add a regression test exercising ImapMessageFetcher::getPart()'s
METHOD-from-body fallback (which is the new branch introduced by this
PR). Uses the existing request_proton_bridge fixture and the same
saveMimeMessage / fetchMessage pattern as the surrounding S/MIME
tests, so it goes through the real Horde+IMAP stack instead of just
parsing the MIME tree like the MessageMapperTest case does.

Asserts that the scheduling entry is emitted, its method is REQUEST,
and the contents we stash contain the METHOD: line we parsed.

AI-assisted: Claude Code (Claude Opus 4.7)
Signed-off-by: Wolfgang Lubowski <w.lub92@gmail.com>

Author: lubo92

tests/Integration/IMAP/ImapMessageFetcherIntegrationTest.php

@@ -230,4 +230,29 @@ public function testFetchMessageWithOpaqueSignedMessage(): void {
 		$this->assertTrue($message->isSigned());
 		$this->assertTrue($message->isSignatureValid());
 	}
+
+	/**
+	 * Proton Mail Bridge strips the `method=` parameter from the
+	 * text/calendar Content-Type during E2E re-assembly. The fetcher must
+	 * fall back to parsing the METHOD: line out of the ICS body, and
+	 * still emit a scheduling entry so downstream rendering picks it up.
+	 */
+	public function testFetchMessageWithImipRequestMissingMethodParam(): void {
+		$rawMessage = file_get_contents(__DIR__ . '/../../data/imip/request_proton_bridge.txt');
+		$uid = $this->saveMimeMessage('INBOX', $rawMessage);
+		$fetcher = $this->fetcherFactory
+			->build(
+				$uid,
+				'INBOX',
+				$this->getTestClient(),
+				$this->account->getUserId()
+			)
+			->withBody(true);
+
+		$message = $fetcher->fetchMessage();
+
+		$this->assertCount(1, $message->scheduling);
+		$this->assertSame('REQUEST', $message->scheduling[0]['method']);
+		$this->assertStringContainsString('METHOD:REQUEST', $message->scheduling[0]['contents']);
+	}
 }