chore: Update copyright year from 2025 to 2026 across core files

- Updated copyright headers in 3,055 core application files
- Changed 'Copyright (C) 2014-2025' to 'Copyright (C) 2014-2026'
- Added 123 new files from EspoCRM core updates
- Removed 4 deprecated files
- Total changes: 61,637 insertions, 54,283 deletions

This is a routine maintenance update for the new year 2026.

application/Espo/Resources/i18n/en_US/Template.json

@@ -21,7 +21,8 @@
         "fontFace": "Font",
         "title": "Title",
         "style": "Style",
-        "status": "Status"
+        "status": "Status",
+        "filename": "Filename"
     },
     "links": {
     },
@@ -48,6 +49,7 @@
         "fontFace": {}
     },
     "tooltips": {
+        "filename": "An optional filename. Entity attributes can be used as placeholders.\n\nAdditional placeholder:\n- `{{today}}`\n\nExample:\n`Document_{{today}}_{{name}}`",
         "footer": "Use {pageNumber} to print page number.",
         "variables": "Copy-paste needed placeholder to Header, Body or Footer."
     }