feat(coding-agent): removed vim edit mode and migrated configs to hashline

- Removed vim edit mode and automatically map existing vim configurations to hashline mode.
- Deleted VimTool class, VimEngine implementation, and all vim-specific editing logic (2409 lines).
- Removed vim mode from EditMode union type, edit tool strategies, and configuration schemas.
- Deleted vim parser, command handler, buffer manager, and renderer modules.
- Updated documentation and tests to remove vim mode references and add deprecation mapping.

packages/coding-agent/src/utils/edit-mode.ts

@@ -1,6 +1,6 @@
 import { $env } from "@oh-my-pi/pi-utils";
 
-export type EditMode = "replace" | "patch" | "hashline" | "vim" | "apply_patch";
+export type EditMode = "replace" | "patch" | "hashline" | "apply_patch";
 
 export const DEFAULT_EDIT_MODE: EditMode = "hashline";
 
@@ -9,7 +9,6 @@ const EDIT_MODE_IDS = {
 	hashline: "hashline",
 	patch: "patch",
 	replace: "replace",
-	vim: "vim",
 } as const satisfies Record<string, EditMode>;
 
 export const EDIT_MODES = Object.keys(EDIT_MODE_IDS) as EditMode[];