Obsidian Vim Mode Support

**What problem does this solve?**
Can type and edit faster

**Proposed Solution**
There should be a hotkey to show the harper menu for the text under the cursor and the buttons should be selectable with HJKL and/or arrow keys, then enter/space to select the desired option.

**Examples**
?

**Component**
idk what this is asking
- [ ] Core engine
- [ ] Plugin/Extension
- [ ] Other: _____

**Additional Context**
Any other relevant info.

Start by locating the Obsidian integration and the Harper menu UI, then trace how keyboard input and hotkeys are handled. Define and verify a hotkey that opens the menu for text under the cursor, with HJKL or arrow navigation and Enter or Space selection.

Written by the indexing model from the issue text.