Parrot 0.15.0

The onboarding got rebuilt after a teardown of a competitor's first-run flow.

• A friendlier permissions screen. Each permission is now a big button that says what it does for you ("Help Parrot hear you", "Help Parrot hear your meeting") and flips to a green confirmation once granted. Same privacy story as always: audio only, never your screen, nothing leaves your Mac.
• A proper finish. The tour ends with a small celebration and a "Let's start" button.
• Replay it any time. Help → Show Welcome Tour, or Settings → General. Handy when permissions act up and you want the guided path again.
• Fixed: source builds crashed at launch. Since 0.14.0, make run produced an app that died instantly (the bundled Sparkle framework needed re-signing with your identity). Downloaded releases were never affected.
• User guide refreshed with the new screens and updated Settings wording.

What's Changed: new onboarding, re-runnable welcome tour, and the dev-build fix in #39

Full Changelog: v0.14.0...v0.15.0