v15.3.0-canary.15

Core Changes

• Upgrade React from c69a5fc5-20250318 to db7dfe05-20250319: #77295
• Turbopack: layout segment optimization for Pages: #74815

Misc Changes

• Update Turbopack production test manifest: #77316
• Update Turbopack development test manifest: #77317
• Update bundler production test manifest: #77314
• fix(turbopack): Call .minify() of lightningcss StyleSheet: #77313

Credits

Huge thanks to @kdy1 and @mischnic for helping!