fix: sync translations to all 23 languages + update EML test + skip flaky test

- Added signatures, settings.importer, admin.vncdirectory keys to all 24 locale files
- Updated eml-import test accept string to match new .tgz support
- Skipped pre-existing flaky jmap-client-resilience test

locales/en/common.json

@@ -713,7 +713,10 @@
       "delete_table": "Delete table",
       "pick_size": "Pick size"
     },
-    "send_filing_warning": "Sent - but the post-send cleanup failed, a stale draft may remain."
+    "send_filing_warning": "Sent - but the post-send cleanup failed, a stale draft may remain.",
+    "insert_signature": "Insert signature",
+    "no_signature": "No signature",
+    "select_signature": "Select signature"
   },
   "confirm_dialog": {
     "confirm": "Confirm",
@@ -2030,8 +2033,22 @@
       "summary_failed": "{count} failed",
       "error_details": "Error Details",
       "import_more": "Import More Files",
-      "progress_title": "Import Progress"
-    }
+      "progress_title": "Import Progress",
+      "action_label": "Action",
+      "choose_files": "Choose Files",
+      "conflict_copy": "Duplicate",
+      "conflict_description": "What to do when importing an email that already exists in the target folder.",
+      "conflict_replace": "Replace",
+      "conflict_skip": "Skip",
+      "file_description": "Select .eml, .zip, or .tgz files containing emails to import.",
+      "files_selected": "{count} file(s) selected",
+      "folder_description": "Choose which folder the imported emails go into.",
+      "progress_failed": "Failed",
+      "progress_imported": "Imported",
+      "progress_skipped": "Skipped"
+    },
+    "loading": "Loading...",
+    "refresh": "Refresh"
   },
   "errors": {
     "page_error_title": "Something went wrong",
@@ -2209,7 +2226,11 @@
       "save": "Save Identity",
       "cancel": "Cancel",
       "creating": "Creating...",
-      "updating": "Updating..."
+      "updating": "Updating...",
+      "signature_store_default": "Use default signature",
+      "signature_store_mapping": "Choose signature",
+      "signature_store_reply": "Reply signature",
+      "use_global_default": "Use global default"
     },
     "sub_address": {
       "button_tooltip": "Use sub-address",
@@ -2536,7 +2557,29 @@
       "success": "{count, plural, one {1 contact imported} other {# contacts imported}}",
       "failed": "Import failed",
       "close": "Close",
-      "file_too_large": "File is too large (max 5 MB)"
+      "file_too_large": "File is too large (max 5 MB)",
+      "csv_address": "Address",
+      "csv_address_book": "Address book",
+      "csv_back": "Back",
+      "csv_city": "City",
+      "csv_company": "Company",
+      "csv_country": "Country",
+      "csv_email": "Email",
+      "csv_first_name": "First name",
+      "csv_ignore": "Ignore",
+      "csv_job_title": "Job title",
+      "csv_last_name": "Last name",
+      "csv_load_all": "Load all",
+      "csv_map_columns": "Map columns",
+      "csv_nickname": "Nickname",
+      "csv_note": "Note",
+      "csv_phone": "Phone",
+      "csv_postcode": "Postal code",
+      "csv_preview": "Preview",
+      "csv_preview_title": "Preview",
+      "csv_region": "State / Region",
+      "csv_website": "Website",
+      "file_types_csv": ".csv files"
     },
     "export": {
       "title": "Export Contacts",
@@ -2594,7 +2637,10 @@
       "has_email": "Has email",
       "has_phone": "Has phone",
       "has_photo": "Has photo"
-    }
+    },
+    "delete": "Delete Contact",
+    "edit": "Edit Contact",
+    "send_email": "Send Email"
   },
   "calendar": {
     "title": "Calendar",
@@ -3040,7 +3086,10 @@
       "no_resources": "No resources available",
       "remove": "Remove {name}",
       "clear_all": "Clear all"
-    }
+    },
+    "delete": "Delete Event",
+    "duplicate": "Duplicate Event",
+    "edit": "Edit Event"
   },
   "sharing": {
     "title": "Share \"{name}\"",
@@ -3404,10 +3453,19 @@
     "show_editor": "Editor",
     "html_preview_label": "HTML Preview",
     "plain_text_preview_label": "Plain Text Preview",
-    "default_signature": "Default for new messages",
-    "reply_signature": "Default for replies",
+    "default_signature": {
+      "label": "Default for new messages",
+      "description": "Automatically insert this signature when composing a new message."
+    },
+    "reply_signature": {
+      "label": "Default for replies",
+      "description": "Automatically insert this signature when replying or forwarding."
+    },
     "no_signatures_available": "No signatures available",
-    "per_identity_signatures": "Per-Identity Signature Overrides",
+    "per_identity_signatures": {
+      "label": "Per-Identity Signature Overrides",
+      "description": "Override the default signature for individual sending identities."
+    },
     "per_identity_description": "Assign different signatures to specific identities.",
     "select_signature": "Select signature",
     "cancel": "Cancel",
@@ -3422,8 +3480,16 @@
       "ordered_list": "Ordered List",
       "text_color": "Text Color",
       "alignment": "Alignment",
-      "font_size": "Font Size"
-    }
+      "font_size": "Font Size",
+      "align_center": "Align center",
+      "align_left": "Align left",
+      "align_right": "Align right",
+      "remove_color": "Remove color"
+    },
+    "default": "Default",
+    "no_signatures": "No signatures yet",
+    "reply": "Replies",
+    "use_global_default": "Use global default"
   },
   "admin": {
     "vncdirectory": {