Add "Convert List Bullets to Em Dash" command

Adds bulletToEmdash() to formatter.ts and registers the new
unicode-formatter:bullet-to-emdash command. Updates README accordingly.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

README.md

@@ -8,6 +8,7 @@ An [Obsidian](https://obsidian.md) plugin that transforms selected text into Uni
 - **Unicode Italic** — converts letters to sans-serif italic (𝘈𝘉𝘊 / 𝘢𝘣𝘤)
 - **Unicode Bold Italic** — converts letters to sans-serif bold italic (𝘼𝘽𝘾 / 𝙖𝙗𝙘)
 - **Remove Unicode Formatting** — converts any formatted Unicode characters back to plain ASCII
+- **Convert List Bullets to Em Dash** — replaces leading `* ` bullet markers with `— ` on each selected line
 - Non-mapped characters (punctuation, spaces, emoji, etc.) are passed through unchanged
 
 ## Usage
@@ -19,6 +20,7 @@ An [Obsidian](https://obsidian.md) plugin that transforms selected text into Uni
    - **Format as Unicode Italic**
    - **Format as Unicode Bold Italic**
    - **Remove Unicode Formatting** — reverses any of the above back to plain ASCII
+   - **Convert List Bullets to Em Dash** — replaces `* ` prefixes with `— `
 
 The selected text is replaced in place.
 
@@ -49,8 +51,8 @@ npm run lint    # ESLint check
 | File | Purpose |
 |------|---------|
 | `src/unicode-maps.ts` | Builds character lookup maps from Unicode code point ranges |
-| `src/formatter.ts` | `transformText(text, style)` and `cleanText(text)` — character mapping functions |
-| `src/commands.ts` | Registers the four editor commands with the Obsidian plugin API |
+| `src/formatter.ts` | `transformText(text, style)`, `cleanText(text)`, and `bulletToEmdash(text)` — text transformation functions |
+| `src/commands.ts` | Registers the five editor commands with the Obsidian plugin API |
 | `src/main.ts` | Plugin entry point — calls `registerCommands` on load |
 
 ### Unicode blocks used