Front-end editing not enabled by default for P2 theme

When the P2 theme is activated, front-end editing is not enabled in the Customizer.

**What I expected**

I expected the front-end editing setting to be automatically enabled when I activated the P2 theme.

**What happened**

Front-end editing was not enabled. I had to do this manually in _Customize_ -> _Theme Options_, after the theme had been activated.

Without front-end editing enabled it is not possible to add the specialized widgets and posts have no front-end editing functionality.

**Steps to reproduce**

- Click My Sites
- Click Themes
- Search for P2 theme
- Activate theme
- Visit site — front-end editing wasn't enabled
- Click My Sites
- Click Customize
- Click Theme Options
- Tick Enable front-end editing
- Save & Publish

To test if this was just a one-off issue I switched themes and then activated P2 again, using the following steps:

- Click My Sites
- Click Themes
- Activate another theme
- Click Back to themes
- Activate P2 theme
- Click Customize
- Click Theme Options

Enable front-end editing was enabled this time.

The issue only seems to appear when activating the theme for the first time — I've tested this across multiple test sites.


I was unable to replicate this issue on my WordPress.org test site.

Issue reported in 834799-f

Start by reproducing first-time P2 activation and inspect the Customizer > Theme Options path for the Enable front-end editing setting. Trace where theme activation establishes its defaults, then compare first activation with reactivation after switching themes. Done means front-end editing is enabled on first activation, allowing the specialized widgets and post editing to work.

Written by the indexing model from the issue text.