## Description

The `omarchy-theme-set-obsidian` script generates theme.css for Obsidian, but it doesn't use the theme's `accent` color defined in `colors.toml` for the `--interactive-accent` CSS variable. Instead, it picks a color from the palette based on frequency sorting, which often results in the wrong accent color being used.

## Expected Behavior

The `--interactive-accent` variable in the generated Obsidian theme.css should use the `accent` color from the theme's `colors.toml` file.

For example, the matte-black theme has:
```toml
accent = "#e68e0d"  # orange
```

The generated theme.css should have:
```css
--interactive-accent: #e68e0d;
```

## Actual Behavior

The script generates:
```css
--interactive-accent: #b90a0a;  # red (from color11 in the palette)
```

This results in Obsidian showing red accent colors instead of orange when using the matte-black theme.

## Steps to Reproduce

1. Set theme to matte-black: `omarchy-theme-set matte-black`
2. Open Obsidian
3. Observe that accent colors (active items, links, etc.) are red instead of orange

## Suggested Fix

In `bin/omarchy-theme-set-obsidian`, the `extract_theme_data()` function should read the `accent` color from `$CURRENT_THEME_DIR/colors.toml` and use it for `--interactive-accent` instead of relying on the frequency-based color slot assignment.

Something like:
```bash
# At the start of extract_theme_data()
local accent_color=""
if [ -f "$CURRENT_THEME_DIR/colors.toml" ]; then
  accent_color=$(grep '^accent = ' "$CURRENT_THEME_DIR/colors.toml" | sed 's/accent = "//;s/"//' | tr '[:upper:]' '[:lower:]')
fi
[ -z "$accent_color" ] && accent_color="${color_slots[8]}"  # fallback to slot

# Then use $accent_color for --interactive-accent
```

## Environment

- Omarchy version: v3.3.0
- Theme: matte-black