Add body read timeout recovery to IMAP client

Introduce Client wrapper with socket deadline support
Add reconnection logic for body read timeouts
Implement test cases for underflow scenarios
Update orchestrator to handle reconnections

internal/imapx/account.go

@@ -4,13 +4,12 @@ import (
 	"context"
 
 	"github.com/emersion/go-imap/v2"
-	"github.com/emersion/go-imap/v2/imapclient"
 )
 
 // FolderMessageCount opens a folder read-only (EXAMINE) and returns how many
 // messages it holds — used to plan an accurate overall progress total before
 // copying begins. It does not fetch any message bodies.
-func FolderMessageCount(c *imapclient.Client, folder string) (int64, error) {
+func FolderMessageCount(c *Client, folder string) (int64, error) {
 	sel, err := c.Select(folder, &imap.SelectOptions{ReadOnly: true}).Wait()
 	if err != nil {
 		return 0, err
@@ -19,7 +18,7 @@ func FolderMessageCount(c *imapclient.Client, folder string) (int64, error) {
 }
 
 // ListFolders returns the mailbox names visible on an already-connected, logged-in client.
-func ListFolders(c *imapclient.Client) ([]string, error) {
+func ListFolders(c *Client) ([]string, error) {
 	mboxes, err := c.List("", "*", nil).Collect()
 	if err != nil {
 		return nil, err