diff --git a/.claude/CLAUDE.md b/.claude/CLAUDE.md
index bb689390..6bc78ed5 100644
--- a/.claude/CLAUDE.md
+++ b/.claude/CLAUDE.md
@@ -53,6 +53,7 @@ Loaded on demand, when a matching file is read (`paths:` frontmatter):
 
 | Rule | Loads for |
 |------|-----------|
+| `.claude/rules/code-style.md` | Kotlin/Compose sources in `main/`, `foss/`, `gplay/`, `debug/` |
 | `.claude/rules/testing.md` | `app/src/test/`, `testFoss/`, `testGplay/` |
 | `.claude/rules/localization.md` | `**/res/values/strings.xml` (base locale) |
 | `.claude/rules/screenshots.md` | Screenshot composables, `screenshotTest/`, fastlane scripts |
diff --git a/.claude/rules/code-style.md b/.claude/rules/code-style.md
new file mode 100644
index 00000000..b629d073
--- /dev/null
+++ b/.claude/rules/code-style.md
@@ -0,0 +1,110 @@
+---
+description: Kotlin and Compose conventions — logging, ViewModel base classes, the ScreenHost/Screen split, DataStore settings
+paths:
+  - "app/src/main/**/*.kt"
+  - "app/src/foss/**/*.kt"
+  - "app/src/gplay/**/*.kt"
+  - "app/src/debug/**/*.kt"
+---
+
+# Code Style
+
+## Logging
+
+`logTag()` builds the tag; `log()` takes a lambda so the message is only built if it's emitted.
+
+```kotlin
+import eu.darken.capod.common.debug.logging.log
+import eu.darken.capod.common.debug.logging.logTag
+import eu.darken.capod.common.debug.logging.Logging.Priority.*
+
+companion object {
+    private val TAG = logTag("Profiles", "Repo")   // multi-part tags are the norm
+}
+
+log(TAG) { "Processing $item" }              // DEBUG is the default
+log(TAG, VERBOSE) { "Devices changed" }
+log(TAG, ERROR) { "Failed: ${e.asLog()}" }   // asLog() for stacktraces
+```
+
+Never suppress protocol logging — downgrading a level is fine, removing the call is not.
+
+## ViewModel base classes
+
+Four exist. Use **`ViewModel4`** for new work — it's the current one (12 subclasses) and wires
+`NavigationEventSource` + `ErrorEventSource2`.
+
+- `ViewModel4` — current, use this
+- `ViewModel2` — plain base, no nav/error event sources (4 subclasses)
+- `ViewModel1` — legacy (1 subclass)
+- `ViewModel3` — **dead, zero subclasses.** It's the `ViewModel4` shape against the older
+  `NavEventSource`/`ErrorEventSource` interfaces. Don't extend it.
+
+## Compose: the Host/Screen split
+
+Every screen is two composables.
+
+**`<Feature>ScreenHost`** — the only place that touches `hiltViewModel()`, installs the event
+handlers, and collects state.
+
+**`<Feature>Screen`** — presentation only. Takes a plain state object plus `on*` callbacks, so it
+previews without Hilt.
+
+```kotlin
+@Composable
+fun SettingsScreenHost(vm: SettingsViewModel = hiltViewModel()) {
+    ErrorEventHandler(vm)
+    NavigationEventHandler(vm)
+
+    val state by vm.state.collectAsStateWithLifecycle(initialValue = null)
+    state?.let {
+        SettingsScreen(
+            state = it,
+            onNavigateUp = { vm.navUp() },
+            onWiki = { vm.openUrl("https://github.com/d4rken-org/capod/wiki") },
+        )
+    }
+}
+
+@Composable
+fun SettingsScreen(
+    state: SettingsViewModel.State,
+    onNavigateUp: () -> Unit,
+    onWiki: () -> Unit,
+    modifier: Modifier = Modifier,   // last, after the required params
+) { ... }
+```
+
+- `modifier: Modifier = Modifier` goes **last**, after required params — not first
+- The Host null-guards state; `collectAsStateWithLifecycle(initialValue = null)` is the usual shape
+- Wrap previews in `PreviewWrapper` (`common/compose/PreviewWrapper.kt`), which applies `CapodTheme`
+  plus a background `Surface`
+- Trailing commas on multi-line parameter lists and argument lists
+
+## DataStore settings
+
+`createValue()` is overloaded. Primitives need no serializer:
+
+```kotlin
+val monitorMode = dataStore.createValue("core.monitor.mode", MonitorMode.AUTOMATIC)
+```
+
+`@Serializable` types take a `Json`, and optionally fall back instead of throwing on corrupt or
+legacy stored JSON:
+
+```kotlin
+val config = dataStore.createValue("some.config", SomeConfig(), json, onErrorFallbackToDefault = true)
+```
+
+Read and write via `.value()` / `.value(x)` (suspend) or `.flow` (reactive). Both `value` functions
+are **extension functions**, not members — see `.claude/rules/testing.md` for what that means when
+mocking.
+
+## General
+
+- Package by feature, not by layer
+- Prefer adding to an existing file over creating a new one
+- Prefer flow-based, cancellable solutions
+- No comments for self-evident code
+- Place `@Suppress` as close to the affected code as possible — on the function or constructor,
+  not the whole class
diff --git a/.claude/rules/pull-requests.md b/.claude/rules/pull-requests.md
index 98c24a9b..7a22e2d3 100644
--- a/.claude/rules/pull-requests.md
+++ b/.claude/rules/pull-requests.md
@@ -47,6 +47,18 @@ Cover only what the diff can't show:
 **Review checklist** — `- [ ]` items, only when there are several non-trivial things to verify.
 A single tricky point stays a Technical Context bullet.
 
+## Labels
+
+Apply labels that match the change. Run `gh label list` to confirm what exists — do not invent new
+ones. Skip labels that don't fit; no labels beats wrong labels.
+
+- **Type**: `bug` for fixes, `enhancement` for new features or improvements
+- **Transport**: `coms/AAP` when the change touches the L2CAP session path, `coms/BLE` when it
+  touches advertisement parsing. Both if it spans the merge in `DeviceMonitor`
+- **Scope**: `device support` for new or fixed pod models, `Translations` for string/locale work,
+  `Build/Deploy` for CI, Gradle, and release tooling
+- `Needs Info/Repro` is a triage label for issues — not for your own PRs
+
 ## Conventions
 
 - Link issues with "Closes #123" / "Fixes #123" / "Resolves #123"
diff --git a/.claude/rules/testing.md b/.claude/rules/testing.md
index 8733e953..a24eb56b 100644
--- a/.claude/rules/testing.md
+++ b/.claude/rules/testing.md
@@ -48,3 +48,31 @@ Each task compiles and runs only its own flavor — running the wrong one silent
 
 CI runs both. Flavor-specific tests are for code that only exists in that flavor — billing in
 `gplay`, the sponsor-based upgrade flow in `foss`.
+
+## Helpers that already exist
+
+- `runTest2(autoCancel, context, expectedError, testBody)` in `testhelpers/coroutine/TestExtensions.kt` —
+  use `expectedError = SomeException::class` instead of hand-rolling a throws-assertion around `runTest`
+- `FakeDataStoreValue<T>(initial)` in `testhelpers/datastore/` — a working fake with a real backing
+  `MutableStateFlow`; read/write it through `.value` and pass `.mock` to the code under test
+
+## Mocking `DataStoreValue`
+
+`DataStoreValue.value()` and `.value(T)` are **extension functions** (`DataStoreValue.kt:54,56`), not
+members, so MockK cannot stub them. They delegate to `flow.first()` and `update { }` — stub those:
+
+```kotlin
+every { someSetting.flow } returns flowOf(value)   // covers .value() reads
+coVerify { someSetting.update(any()) }             // verifies .value(x) writes
+```
+
+`UpgradeRepoGplayTest` uses this shape. Prefer `FakeDataStoreValue` when you need reads and writes to
+actually round-trip.
+
+## Reading ViewModel state
+
+`ViewModel2.asLiveState()` is `stateIn(..., initialValue = null).filterNotNull()` with
+`SharingStarted.WhileSubscribed(5_000)` — so `vm.state` is a `Flow`, not a `StateFlow`, and has no
+`.value` to read. Collect it: `vm.state.first()` is the established pattern across the existing
+ViewModel tests. Because the upstream only runs while subscribed, a test that never collects sees
+nothing happen at all.