Add Mail integration: search, read, and save attachments via AppleScript

Lets the AI search Apple Mail, read a message, and save an attachment to
disk (e.g. to hand off to paperless_upload_document) — e.g. "find the
receipt from Elkjøp and add it to Paperless." Talks to Mail.app via
AppleScript/Apple Events rather than parsing its private on-disk store,
so no Full Disk Access or MIME parsing is needed; Mail's own attachment
save handles all decoding. Every mail_* tool call requires approval
(Deny/Allow Once/Allow for Session), mirroring the bash_execute and
Personal Data gate pattern.

Also fixes a pre-existing bug found while touching the adjacent
tool-activation condition: paperlessEnabled was missing from it, so
Paperless tools could fail to activate unless another integration was
also active.

oAI/ViewModels/ChatViewModel.swift

@@ -1010,6 +1010,8 @@ Don't narrate future actions ("Let me...") - just use the tools.
         let personalDataActive = settings.calendarEnabled || settings.remindersEnabled || settings.contactsEnabled || settings.locationMapsEnabled
         let researchAgentsActive = settings.agentsEnabled
         let externalMCPActive = !settings.externalMCPServers.filter { $0.isEnabled }.isEmpty
+        let mailActive = settings.mailEnabled
+        let paperlessActive = settings.paperlessEnabled && settings.paperlessConfigured
         // Dedicated images API path (OpenRouter /images endpoint — separate from chat completions)
         if selectedModel?.capabilities.usesImagesAPI == true,
            let orProvider = provider as? OpenRouterProvider {
@@ -1018,7 +1020,7 @@ Don't narrate future actions ("Let me...") - just use the tools.
         }
 
         let modelSupportTools = selectedModel?.capabilities.tools ?? false
-        if modelSupportTools && (anytypeActive || bashActive || personalDataActive || researchAgentsActive || externalMCPActive || (mcpActive && !mcp.allowedFolders.isEmpty)) {
+        if modelSupportTools && (anytypeActive || bashActive || personalDataActive || researchAgentsActive || externalMCPActive || mailActive || paperlessActive || (mcpActive && !mcp.allowedFolders.isEmpty)) {
             generateAIResponseWithTools(provider: provider, modelId: modelId)
             return
         }