implemented 10-cli-commands.md: added CLI commands for branch name resolution, one-shot builds, failed build retries, and build status reports; includes tests for functionality and edge cases

src/test/kotlin/de/hoennig/gittally/commands/CapturedConsole.kt

@@ -0,0 +1,26 @@
+package de.hoennig.gittally.commands
+
+import java.io.ByteArrayOutputStream
+import java.io.PrintStream
+
+data class CapturedConsole(
+    val stdout: String,
+    val stderr: String,
+)
+
+/** Captures `System.out` and `System.err` while [block] runs. */
+fun captureConsole(block: () -> Unit): CapturedConsole {
+    val out = ByteArrayOutputStream()
+    val err = ByteArrayOutputStream()
+    val previousOut = System.out
+    val previousErr = System.err
+    System.setOut(PrintStream(out, true))
+    System.setErr(PrintStream(err, true))
+    try {
+        block()
+    } finally {
+        System.setOut(previousOut)
+        System.setErr(previousErr)
+    }
+    return CapturedConsole(out.toString(), err.toString())
+}