feat(mail): IMAP client — select, fetch headers/full, search

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

internal/mail/imap_integration_test.go

@@ -0,0 +1,59 @@
+//go:build integration
+
+package mail
+
+import (
+	"os"
+	"strconv"
+	"testing"
+)
+
+// These tests require a GreenMail server reachable via env vars:
+//
+//	EMCLI_TEST_IMAP_HOST, EMCLI_TEST_IMAP_PORT, EMCLI_TEST_USER, EMCLI_TEST_PASS
+//
+// Run: go test -tags=integration ./internal/mail/
+func testCfg(t *testing.T) IMAPConfig {
+	t.Helper()
+	host := os.Getenv("EMCLI_TEST_IMAP_HOST")
+	if host == "" {
+		t.Skip("EMCLI_TEST_IMAP_HOST not set; skipping IMAP integration test")
+	}
+	return IMAPConfig{
+		Host:     host,
+		Port:     atoiEnv(t, "EMCLI_TEST_IMAP_PORT"),
+		Security: "starttls",
+		Username: os.Getenv("EMCLI_TEST_USER"),
+		Password: os.Getenv("EMCLI_TEST_PASS"),
+	}
+}
+
+func TestSelectAndFetch(t *testing.T) {
+	c, err := Dial(testCfg(t))
+	if err != nil {
+		t.Fatalf("Dial: %v", err)
+	}
+	defer c.Logout()
+
+	uidv, maxUID, err := c.SelectFolder("INBOX")
+	if err != nil {
+		t.Fatalf("SelectFolder: %v", err)
+	}
+	if uidv == 0 {
+		t.Fatal("uidvalidity should be non-zero")
+	}
+	headers, err := c.FetchHeaders("INBOX", nil)
+	if err != nil {
+		t.Fatalf("FetchHeaders: %v", err)
+	}
+	t.Logf("inbox has %d messages, maxUID=%d", len(headers), maxUID)
+}
+
+func atoiEnv(t *testing.T, k string) int {
+	t.Helper()
+	n, err := strconv.Atoi(os.Getenv(k))
+	if err != nil {
+		t.Fatalf("bad int env %s: %v", k, err)
+	}
+	return n
+}