Extract build-logic + migrate to AGP 9

[ZacSweers]

Unfortunately large change but this migration was a mess at the gradle level. Moved things to build-logic first (future project isolation work hopefully). Purely non-functional though, no prod sources changed!

Most of the line diff is deceiving and just classpath file moves and sample app file moves. For review I would focus on build-logic/**.*.kts files and build files

Other stuff

• Lint appears to inexplicably always run with checkDependencies = true in application projects if they detect any KMP project dependencies. Filed https://issuetracker.google.com/issues/501744304
• Extracted application projects for various samples since KMP android projects can only be libraries now
• Android runtime classpath is a different name in KMP projects now, so had to regen dependency guard baselines
• Cleaned up some wrong groupings for source sets (wrapping them in common {})
• Remove kapt completely (only left in the tacos sample)
• ewtf plugin appears to have a race condition in KMP projects so I have to apply it last, will raise over to them
• Speed up unit tests using maxParallelForks

[stagg]

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