SPEC v0.1 and project rules for Kvitt

Write SPEC.md v0.1 from the owner interview (requirements, data model,
stack, API outline, security, business rules, deployment, milestones,
UX sprint brief, contracts). Fill the CLAUDE.md blanks, move the Gradle
pin files into android/, point the tools at android/ and server/, and
record the git bootstrap exception in the handoff.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

android/gradle.properties

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+org.gradle.jvmargs=-Xmx4g -Dfile.encoding=UTF-8
+org.gradle.parallel=true
+org.gradle.caching=true
+org.gradle.configuration-cache=true
+android.useAndroidX=true
+android.nonTransitiveRClass=true
+kotlin.code.style=official
+# Pinned JDK: Homebrew openjdk@25 (current LTS). A versioned formula does not move under the build; the unversioned
+# `openjdk` on PATH does. Run ./gradlew from any shell and never set JAVA_HOME. Bytecode still targets Java 17.
+org.gradle.java.installations.paths=/opt/homebrew/opt/openjdk@25/libexec/openjdk.jdk/Contents/Home
+# Nothing is downloaded: if openjdk@25 is missing the build says so.
+org.gradle.java.installations.auto-download=false

android/gradle/gradle-daemon-jvm.properties

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+# Gradle daemon JVM: JDK 25, the current LTS. Bytecode still targets Java 17.
+toolchainVersion=25