[renaudmathieu]

First two phases of the 2026-10-20 repository audit: repo hygiene, documentation drift, and everything that stood between the two libraries and a publishable artifact. No behaviour change in the sync protocol; that is a separate PR.

Publishability of :crdt and :sync

• Drop -Xexplicit-backing-fields. The flag marks every compiled class as produced by a pre-release Kotlin compiler (xi=50 in the class metadata), so any consumer of com.doppio.syncdo:sync would fail with "class compiled with a pre-release version of Kotlin". The sample :server already worked around it with -Xskip-prerelease-check under a wrong diagnosis; that flag is removed too. SyncEngine.syncStatus and the sample repository now use the classic private MutableStateFlow + asStateFlow() pattern. Verified with javap: xi=48 on the rebuilt classes.
• explicitApi() on both libraries, with public on every declaration. The API baselines (api/*.api) are unchanged, which confirms nothing was accidentally public.
• Pinned JVM bytecode level. The jvm() target had no jvmTarget, so the published -jvm jar followed whichever JDK ran Gradle (Java 17 class files locally). It now targets Java 11 like the Android target (major version: 55 verified).
• Maven Central configuration: publishToMavenCentral(CENTRAL_PORTAL) + signAllPublications(). publishToMavenLocal still works with no signing key configured (verified).
• Removed two unused :sync dependencies (ktor-client-content-negotiation, ktor-serialization-kotlinx-json) and the redundant applyDefaultHierarchyTemplate() calls.

CI

• New ci.yml on pull requests and main: Linux job runs :crdt:check :sync:check (tests, apiCheck, Android lint), the sample JVM tests, and compiles the desktop and Android app; macOS job runs the iOS simulator tests of both libraries.
• New publish.yml on v* tags, publishing both libraries to Maven Central with the version taken from the tag. Needs the MAVEN_CENTRAL_USERNAME, MAVEN_CENTRAL_PASSWORD, SIGNING_KEY and SIGNING_KEY_PASSWORD secrets.
• docs.yml now uses JDK 21 (the desktop app requires a 21 toolchain at configuration time, even for library-only tasks) and has a timeout.

Hygiene

• data/syncdo-state.json was tracked runtime state, rewritten by every IDE run of the server from the repo root. It is removed from the index, and data/ plus server/data/ are ignored.
• The sample server's state directory is now a parameter of Application.module, so ApplicationTest runs against a temp directory instead of the developer's state. Root log level goes from trace to info.
• Desktop window title no longer contains an em dash.
• .claude/settings.local.json and .claude/worktrees/ ignored for other contributors.

Docs

• CLAUDE.md: getLocalClock is not suspending; design.pen lives under design/.
• sync/Module.md: PullRequest and PushDelta carry a nodeId.
• README.md: the libraries are not on Maven Central yet, so the install snippet points at mavenLocal(); prerequisites say JDK 17+ (not 11+); the state directory doc explains the server/data/ path.
• crdt/README.md: kotlin.time.Instant is stable since Kotlin 2.2, not 2.1.
• CONTRIBUTING.md: mentions CI and explicit API mode. CHANGELOG.md: entries for the above.

Verification

• ./gradlew :crdt:check :sync:check :composeApp:jvmJar (same as the Linux CI job, plus iOS simulator tests locally)
• ./gradlew :shared:jvmTest :server:test :crdt:apiCheck :sync:apiCheck
• ./gradlew :crdt:publishToMavenLocal :sync:publishToMavenLocal without a signing key
• ./gradlew dokkaGenerate with no Undocumented warning
• javap -v on the rebuilt classes: xi=48, major version: 55

Not in this PR (later phases of the audit)

Sync correctness (lost pushes when the socket dies, in-memory outbox, status stuck in Syncing, malformed frames, clock validation on the server), library API reshaping before 0.1.0 (LwwRegister same-instant writes, OrSet invariant on deserialization, data classes as ABI, SyncEngine constructor), and the sample-app items.