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>

Apps/MagnumOpus/ContentView.swift

@@ -163,9 +163,7 @@ struct ContentView: View {
 		do {
 			try viewModel.setup(config: config, credentials: credentials)
 			try KeychainService.saveCredentials(credentials, for: config.id)
-			if let data = try? JSONEncoder().encode(config) {
-				UserDefaults.standard.set(data, forKey: "accountConfig")
-			}
+			Self.saveAccountConfig(config)
 			Task {
 				await viewModel.syncNow()
 				await viewModel.loadMailboxes(accountId: config.id)
@@ -178,8 +176,7 @@ struct ContentView: View {
 	}
 
 	private func loadExistingAccount() {
-		guard let data = UserDefaults.standard.data(forKey: "accountConfig"),
-			  let config = try? JSONDecoder().decode(AccountConfig.self, from: data),
+		guard let config = Self.loadAccountConfig(),
 			  let credentials = try? KeychainService.loadCredentials(for: config.id)
 		else { return }
 		do {
@@ -196,6 +193,40 @@ struct ContentView: View {
 	}
 }
 
+extension ContentView {
+	/// Store account config in Application Support (not UserDefaults) for reliability.
+	static func saveAccountConfig(_ config: AccountConfig) {
+		let url = accountConfigURL
+		let dir = url.deletingLastPathComponent()
+		try? FileManager.default.createDirectory(at: dir, withIntermediateDirectories: true)
+		if let data = try? JSONEncoder().encode(config) {
+			try? data.write(to: url, options: .atomic)
+		}
+	}
+
+	static func loadAccountConfig() -> AccountConfig? {
+		// Try Application Support first, then migrate from UserDefaults
+		if let data = try? Data(contentsOf: accountConfigURL),
+		   let config = try? JSONDecoder().decode(AccountConfig.self, from: data) {
+			return config
+		}
+		// Migrate from UserDefaults if present
+		if let data = UserDefaults.standard.data(forKey: "accountConfig"),
+		   let config = try? JSONDecoder().decode(AccountConfig.self, from: data) {
+			saveAccountConfig(config)
+			UserDefaults.standard.removeObject(forKey: "accountConfig")
+			return config
+		}
+		return nil
+	}
+
+	private static var accountConfigURL: URL {
+		FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)[0]
+			.appendingPathComponent("MagnumOpus", isDirectory: true)
+			.appendingPathComponent("accountConfig.json")
+	}
+}
+
 // Wrapper to make ComposeMode Identifiable for .sheet(item:)
 struct ComposeModeWrapper: Identifiable {
 	let id = UUID()

Apps/MagnumOpus/ViewModels/MailViewModel.swift

@@ -2,6 +2,7 @@ import SwiftUI
 import GRDB
 import Models
 import MailStore
+import MIMEParser
 import SyncEngine
 import IMAPClient
 import SMTPClient
@@ -152,9 +153,11 @@ final class MailViewModel {
 		do {
 			let records = try store.mailboxes(accountId: accountId)
 			mailboxes = records.map { record in
-				MailboxInfo(
+				let unread = (try? store.unreadMessageCount(mailboxId: record.id)) ?? 0
+				let total = (try? store.totalMessageCount(mailboxId: record.id)) ?? 0
+				return MailboxInfo(
 					id: record.id, accountId: record.accountId,
-					name: record.name, unreadCount: 0, totalCount: 0
+					name: record.name, unreadCount: unread, totalCount: total
 				)
 			}
 			if selectedMailbox == nil, let inbox = mailboxes.first(where: { $0.name.lowercased() == "inbox" }) {
@@ -231,14 +234,10 @@ final class MailViewModel {
 
 			switch perspective {
 			case .inbox:
-				// Emails in INBOX with no deferral
+				// Emails in INBOX with no deferral (single SQL query)
 				if let inboxMailbox = mailboxes.first(where: { $0.name.lowercased() == "inbox" }) {
-					let msgs = try store.messages(mailboxId: inboxMailbox.id)
+					let msgs = try store.inboxMessagesExcludingDeferred(mailboxId: inboxMailbox.id)
 					for msg in msgs {
-						// Skip deferred emails
-						if let _ = try? store.deferralForMessage(messageId: msg.id) {
-							continue
-						}
 						result.append(.email(MailStore.toMessageSummary(msg)))
 					}
 				}
@@ -312,15 +311,10 @@ final class MailViewModel {
 		var counts: [Perspective: Int] = [:]
 
 		do {
-			// Inbox count
+			// Inbox count (single SQL query instead of N+1)
 			var inboxCount = 0
 			if let inboxMailbox = mailboxes.first(where: { $0.name.lowercased() == "inbox" }) {
-				let msgs = try store.messages(mailboxId: inboxMailbox.id)
-				for msg in msgs {
-					if (try? store.deferralForMessage(messageId: msg.id)) == nil {
-						inboxCount += 1
-					}
-				}
+				inboxCount = try store.inboxMessageCountExcludingDeferred(mailboxId: inboxMailbox.id)
 			}
 			inboxCount += try store.inboxTasks(accountId: accountId).count
 			counts[.inbox] = inboxCount
@@ -649,18 +643,20 @@ final class MailViewModel {
 		let client = provider()
 		do {
 			try await client.connect()
-			let (text, html) = try await client.fetchBody(uid: record.uid)
+			let rawMessage = try await client.fetchFullMessage(uid: record.uid)
 			try? await client.disconnect()
-			if text != nil || html != nil {
-				try store.storeBody(messageId: message.id, text: text, html: html)
-				var updated = message
-				updated.bodyText = text
-				updated.bodyHtml = html
-				return updated
+			if !rawMessage.isEmpty {
+				let parsed = MIMEParser.parse(rawMessage)
+				if parsed.textBody != nil || parsed.htmlBody != nil {
+					try store.storeBody(messageId: message.id, text: parsed.textBody, html: parsed.htmlBody)
+					var updated = message
+					updated.bodyText = parsed.textBody
+					updated.bodyHtml = parsed.htmlBody
+					return updated
+				}
 			}
 		} catch {
 			try? await client.disconnect()
-			// Offline or fetch failed — compose without quoted text
 		}
 		return message
 	}

Apps/MagnumOpus/Views/ThreadDetailView.swift

@@ -187,7 +187,7 @@ struct StatusBadge: View {
 
 struct MessageView: View {
 	let message: MessageSummary
-	@State private var showHTML = false
+	@State private var showSource = false
 
 	var body: some View {
 		VStack(alignment: .leading, spacing: 8) {
@@ -195,9 +195,9 @@ struct MessageView: View {
 				Text(message.from?.displayName ?? "Unknown")
 					.fontWeight(.semibold)
 				Spacer()
-				if message.bodyHtml != nil {
-					Toggle(isOn: $showHTML) {
-						Text("HTML")
+				if message.bodyHtml != nil && message.bodyText != nil {
+					Toggle(isOn: $showSource) {
+						Text("Plain")
 							.font(.caption)
 					}
 					.toggleStyle(.button)
@@ -214,13 +214,17 @@ struct MessageView: View {
 					.foregroundStyle(.secondary)
 			}
 
-			if showHTML, let html = message.bodyHtml {
-				MessageWebView(html: html)
-					.frame(minHeight: 200)
-			} else if let bodyText = message.bodyText {
+			if showSource, let bodyText = message.bodyText {
 				Text(bodyText)
 					.font(.body)
 					.textSelection(.enabled)
+			} else if let html = message.bodyHtml {
+				MessageWebView(html: html)
+					.frame(minHeight: 200)
+			} else if let bodyText = message.bodyText {
+				// Render plain text as HTML for proper Unicode/emoji rendering
+				MessageWebView(html: plainTextToHTML(bodyText))
+					.frame(minHeight: 100)
 			} else if let snippet = message.snippet {
 				Text(snippet)
 					.font(.body)
@@ -234,4 +238,13 @@ struct MessageView: View {
 		}
 		.padding()
 	}
+
+	private func plainTextToHTML(_ text: String) -> String {
+		let escaped = text
+			.replacingOccurrences(of: "&", with: "&")
+			.replacingOccurrences(of: "<", with: "&lt;")
+			.replacingOccurrences(of: ">", with: "&gt;")
+			.replacingOccurrences(of: "\n", with: "<br>")
+		return "<pre style=\"white-space: pre-wrap; word-wrap: break-word; font-family: -apple-system, system-ui; font-size: 14px;\">\(escaped)</pre>"
+	}
 }