fix remaining code review issues, add HTML email rendering, charset-aware MIME decoding

- add charset-aware string decoding in MIMEParser (supports UTF-8, Latin-1, Windows-1252, etc.)
- fix prefetchBodies: remove broken ISO8601 date filter that prevented body fetching
- fix ensureBodyLoaded to use fetchFullMessage + MIMEParser instead of broken fetchBody
- add N+1 query fix: inboxMessagesExcludingDeferred uses SQL LEFT JOIN instead of per-message deferral check
- add inboxMessageCountExcludingDeferred for efficient perspective counts
- add unreadMessageCount, totalMessageCount queries to MailStore
- wire mailbox unread/total counts in loadMailboxes (were hardcoded to 0)
- add flag sync: reconcileFlags fetches flags for existing UIDs, updates local read/flagged state
- move account config from UserDefaults to Application Support file, auto-migrate existing config
- render HTML emails by default (toggle to plain text), render plain text as HTML for proper Unicode/emoji
- replace print() with os_log Logger in SyncCoordinator

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Packages/MagnumOpusCore/Sources/SyncEngine/SyncCoordinator.swift

@@ -1,10 +1,13 @@
 import Foundation
+import os
 import Models
 import IMAPClient
 import MailStore
 import MIMEParser
 import TaskStore
 
+private let logger = Logger(subsystem: "de.felixfoertsch.MagnumOpus", category: "SyncCoordinator")
+
 @Observable
 @MainActor
 public final class SyncCoordinator {
@@ -84,7 +87,7 @@ public final class SyncCoordinator {
 			}
 		} catch {
 			// Resurfacing is non-fatal; log and continue
-			print("[SyncCoordinator] resurfaceDeferrals error: \(error)")
+			logger.warning("[SyncCoordinator] resurfaceDeferrals error: \(error)")
 		}
 	}
 
@@ -168,6 +171,11 @@ public final class SyncCoordinator {
 			emit(.newMessages(count: envelopes.count, mailbox: remoteMailbox.name))
 		}
 
+		// Reconcile flags for existing messages (read/unread state from other devices)
+		if lastUid > 0 {
+			await reconcileFlags(mailboxId: mailboxId, uidRange: 1...lastUid)
+		}
+
 		await prefetchBodies(mailboxId: mailboxId)
 
 		// Detect and store mailbox role from LIST attributes
@@ -183,14 +191,30 @@ public final class SyncCoordinator {
 		)
 	}
 
+	/// Reconcile read/flagged state for existing messages with the server.
+	private func reconcileFlags(mailboxId: String, uidRange: ClosedRange<Int>) async {
+		do {
+			let remoteFlagPairs = try await imapClient.fetchFlags(uids: uidRange)
+			let localMessages = try store.messages(mailboxId: mailboxId)
+			let localByUid = Dictionary(localMessages.map { ($0.uid, $0) }, uniquingKeysWith: { first, _ in first })
+
+			for pair in remoteFlagPairs {
+				guard let local = localByUid[pair.uid] else { continue }
+				if local.isRead != pair.isRead || local.isFlagged != pair.isFlagged {
+					try store.updateFlags(messageId: local.id, isRead: pair.isRead, isFlagged: pair.isFlagged)
+				}
+			}
+		} catch {
+			// Flag reconciliation is non-fatal
+			logger.warning("[SyncCoordinator] reconcileFlags error: \(error)")
+		}
+	}
+
 	/// Fetch full RFC822 messages and parse MIME for body + attachments
 	private func prefetchBodies(mailboxId: String) async {
-		let thirtyDaysAgo = ISO8601DateFormatter().string(
-			from: Calendar.current.date(byAdding: .day, value: -30, to: Date())!
-		)
 		do {
 			let messages = try store.messages(mailboxId: mailboxId)
-			let recent = messages.filter { $0.bodyText == nil && $0.bodyHtml == nil && $0.date >= thirtyDaysAgo }
+			let recent = messages.filter { $0.bodyText == nil && $0.bodyHtml == nil }
 			for message in recent.prefix(50) {
 				guard !Task.isCancelled else { break }
 				let rawMessage = try await imapClient.fetchFullMessage(uid: message.uid)
@@ -221,7 +245,7 @@ public final class SyncCoordinator {
 			}
 		} catch {
 			// Background prefetch failure is non-fatal
-			print("[SyncCoordinator] prefetchBodies error: \(error)")
+			logger.warning("[SyncCoordinator] prefetchBodies error: \(error)")
 		}
 	}
 
@@ -300,14 +324,14 @@ public final class SyncCoordinator {
 	/// Must be called after at least one successful sync (so capabilities are cached).
 	public func startIdleMonitoring() async {
 		guard let credentials else {
-			print("[SyncCoordinator] No credentials provided, cannot start IDLE")
+			logger.warning("[SyncCoordinator] No credentials provided, cannot start IDLE")
 			return
 		}
 
 		do {
 			let caps = try await imapClient.capabilities()
 			guard caps.contains("IDLE") else {
-				print("[SyncCoordinator] Server does not support IDLE, using periodic sync only")
+				logger.warning("[SyncCoordinator] Server does not support IDLE, using periodic sync only")
 				return
 			}
 
@@ -326,7 +350,7 @@ public final class SyncCoordinator {
 				}
 			}
 		} catch {
-			print("[SyncCoordinator] Failed to start IDLE monitoring: \(error)")
+			logger.warning("[SyncCoordinator] Failed to start IDLE monitoring: \(error)")
 		}
 	}