feat: improve LSP lifecycle, terminal widget, and code folding support

- LSP:
  - Add shutdown and exit request/notification handling
  - Send initialized notification after initialize response
  - Gracefully close clients with delayed shutdown via GLib timeout
  - Fix LSP WS server ↔ Godot LSP communication flow

- Terminal (VteWidget):
  - Switch to async spawn with full environment inheritance
  - Add PROMPT_COMMAND OSC7 support for cwd tracking
  - Improve UX: scrollback, no audible bell, auto scroll
  - Implement clipboard shortcuts, selection copy, middle-click paste
  - Track cwd changes and update UI label
  - Add proper signal wiring and cleanup on destroy

- Code folding:
  - Add fold support for JS, HTML, CSS, JSON, C, C++, Go
  - Reset fold state safely when AST or filetype is unavailable

- UI (Plugins dialog):
  - Improve dialog behavior (non-modal, centered, transient)
  - Add focus-out auto-hide and Ctrl+Shift+P shortcut

- Misc:
  - Add type hints in VTE widget
  - Update TODOs (remove completed items, add LSP comm fix)
  - Add terminal plugin scaffolding

TODO.md

@@ -1,7 +1,5 @@
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 ### Add
-1. Add Godot LSP Client
-1. Add Terminal plugin
 1. Add <Ctrl\>i to **lsp_manager** to list who implements xyz
 
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@@ -10,8 +8,8 @@ ___
 
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 ### Fix
+- Fix LSP WS Server to Godot LSP Server communication
 - Fix <Ctrl\>z in multi-insert mode being funky. Insure updates happen on block level.
        I.E, maybe push updates to queue to insure block undo/redo?
-- Fix on lsp client unload to close files lsp side and unload server endpoint
 
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