Feature: Smart Dialogue Input Editor

[CWolfs]

Upgrade the dialogue text input into a smarter raw editor.

The editor should still preserve the raw BattleTech dialogue text, but make it easier to write safely.

For this change:

• Add syntax highlighting for BattleTech dialogue tags and ExtendedConversations interpolation tags
• Add autocomplete for common replacements like {COMMANDER.FirstName}
• Add autocomplete for data manager tooltip tags like [[DM.BaseDescriptionDefs[...],...]]
• Add autocomplete for ExtendedConversations tags like <Game.CurrentDate> and <Stats.Company.SomeStat>
• Validate malformed tags and show inline warnings
• Provide a preview of how known tags will render where possible
• Allow operation/tag autocomplete rules to be extended from JSON definition/config files
• Keep a raw editing mode as the source of truth