chore(agents): document local.properties resolution for worktrees

AGENTS.md

@@ -53,9 +53,28 @@ When the user provides an issue number to work on, the agent works in a dedicate
    ```
 
 4. `cd` into the worktree and continue all subsequent work there. Run `./gradlew`, tests, and the IDE from inside the worktree — never edit files in the main checkout.
+5. **Resolve `local.properties` before any Gradle command.** It's gitignored, so a fresh worktree has no `sdk.dir` and `./gradlew` will fail to locate the Android SDK. Create `local.properties` at the worktree root with one line:
+   ```properties
+   sdk.dir=/absolute/path/to/Android/sdk
+   ```
+   See [Finding the Android SDK path](#finding-the-android-sdk-path) below. If `local.properties` already exists in the worktree, leave it alone. Do not commit this file.
 
 If the worktree for that issue already exists (resuming work, or another agent on the same issue), `cd` into it and `git pull` — do not create a duplicate.
 
+**Finding the Android SDK path**
+
+If you accepted Android Studio's default install location, the SDK lives at one of these:
+
+- **macOS:** `/Users/<you>/Library/Android/sdk`
+- **Linux:** `/home/<you>/Android/Sdk`
+- **Windows:** `C:\Users\<you>\AppData\Local\Android\Sdk`
+
+To confirm the exact path on any machine, open Android Studio → Settings → Languages & Frameworks → Android SDK — the "Android SDK Location" field shows the absolute path. Alternatively, if `ANDROID_HOME` or `ANDROID_SDK_ROOT` is set in your shell environment, Gradle picks that up automatically and `local.properties` is not required.
+
+Notes on the file format:
+- Use forward slashes and no quoting (even on Windows if you're on a Unix shell, or on macOS/Linux which is the project's platform).
+- The path is per-machine, not per-project. Every worktree needs its own `local.properties` pointing at the local SDK.
+
 **Conventions:**
 
 - Worktree path: `../ledgerr-<branch-with-slashes-as-dashes>` (sibling of the main checkout, not nested inside it)