[docs][refactor] update README/CHANGELOG for maxLogcatEntries + refactor LogcatDataSource (#249)

## Summary by CodeRabbit

* **Refactor**
  * [LogcatDataSource] Swap Runtime.getRuntime().exec(String) for ProcessBuilder with an explicit argument list, in both the streaming producer and the one-shot snapshot capture

* **Documentation**
  * Updated changelog with new capabilities.
  * Added configuration guide for customizing logcat buffer limits.

Author: Manabu-GT

CHANGELOG.md

@@ -5,6 +5,7 @@
 ### New Features
 
 * **Thermal status row** – Optional thermal-status indicator for the compact overlay, opt-in via `OverlayMode.FullMetrics(showThermal = true)`. Combines `PowerManager.getCurrentThermalStatus()` with `getThermalHeadroom()` per [Google's ADPF guidance](https://developer.android.com/games/optimize/adpf/thermal#device-limitations-of-the-thermal-api) so devices with an incomplete thermal HAL still surface a useful signal. Requires Android 11 (API 30) or above; row stays hidden on older devices. Resolves [#246](https://github.com/Manabu-GT/DebugOverlay-Android/issues/246).
+* **Configurable Logcat buffer size** – New `Config.maxLogcatEntries` controls how many entries the built-in Logcat tab retains (default 300). Also bounds `logcat -T N` / `-t N` so it caps OS replay on panel open and on bug-report snapshots. Reassignable at runtime via `DebugOverlay.configure { maxLogcatEntries = … }`.
 
 ## Version 2.5.0 *(2026-05-12)*
 

README.md

@@ -191,6 +191,18 @@ DebugOverlay.configure {
 
 The row shows the current thermal-throttling level with a color-coded dot. Labels are abbreviated to fit the compact panel — `None` / `Light` / `Mod` / `Sev` / `Crit` / `Emer` / `Shut` — mapping to `PowerManager.THERMAL_STATUS_NONE` / `_LIGHT` / `_MODERATE` / `_SEVERE` / `_CRITICAL` / `_EMERGENCY` / `_SHUTDOWN` respectively. Requires Android 11 (API 30) or above with a working thermal HAL — the row stays hidden on older devices and on API 30+ devices whose HAL doesn't expose `getThermalHeadroom` data. If the HAL later starts reporting, the row appears on the next poll.
 
+### Logcat buffer size
+
+The built-in Logcat tab keeps the last 300 entries by default. Override via `maxLogcatEntries`:
+
+```kotlin
+DebugOverlay.configure {
+  maxLogcatEntries = 1000
+}
+```
+
+The value also bounds the `logcat -T N` / `-t N` calls, so it caps how many lines the OS replays when the panel opens and when a bug report snapshot is captured.
+
 ### Network request tracking
 
 ```kotlin

debugoverlay-core/src/main/kotlin/com/ms/square/debugoverlay/internal/data/source/LogcatDataSource.kt

@@ -39,7 +39,7 @@ import kotlin.time.Duration.Companion.milliseconds
 internal class LogcatDataSource(
   scope: CoroutineScope,
   private val parser: LogcatEntryParser = LogcatEntryParser(),
-  initialMaxEntries: Int,
+  @IntRange(from = 1) initialMaxEntries: Int,
 ) : LogSource,
   Clearable,
   Closeable {
@@ -91,9 +91,15 @@ internal class LogcatDataSource(
     try {
       /**
        * NOTE: The -T flag with a number fetches the last N lines from this app and continue to listens
-       * for new logs (-t option fetches once and exists immediately).
+       * for new logs (-t option fetches once and exits immediately).
        */
-      val process = Runtime.getRuntime().exec("logcat -v threadtime,printable,epoch -T $maxEntries").also {
+      val process = ProcessBuilder(
+        "logcat",
+        "-v",
+        "threadtime,printable,epoch",
+        "-T",
+        maxEntries.toString()
+      ).start().also {
         synchronized(processLock) {
           currentProcess = it
         }
@@ -167,8 +173,13 @@ internal class LogcatDataSource(
   private suspend fun captureLogcatOnce(): List<LogEntry> = withContext(Dispatchers.IO) {
     buildList {
       // -t N = fetch N recent lines and EXIT (vs -T which streams continuously)
-      val process = Runtime.getRuntime()
-        .exec("logcat -v threadtime,printable,epoch -t $maxEntries")
+      val process = ProcessBuilder(
+        "logcat",
+        "-v",
+        "threadtime,printable,epoch",
+        "-t",
+        maxEntries.toString()
+      ).start()
 
       try {
         InputStreamReader(process.inputStream).useLines { lines ->