feat(dolt): auto-commit write commands and set explicit commit authors (#1270)

Adds Dolt auto-commit functionality for write commands and sets explicit commit authors.

Includes fix for race condition in commandDidWrite (converted to atomic.Bool).

Original PR: #1267 by @coffeegoddd
Co-authored-by: Dustin Brown <dustin@dolthub.com>

cmd/bd/dolt_autocommit_test.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"errors"
+	"testing"
+)
+
+func TestFormatDoltAutoCommitMessage(t *testing.T) {
+	msg := formatDoltAutoCommitMessage("update", "alice", []string{"bd-2", "bd-1", "bd-2", "", "bd-3"})
+	if msg != "bd: update (auto-commit) by alice [bd-1, bd-2, bd-3]" {
+		t.Fatalf("unexpected message: %q", msg)
+	}
+
+	// Caps IDs (max 5) and sorts
+	msg = formatDoltAutoCommitMessage("create", "bob", []string{"z-9", "a-1", "m-3", "b-2", "c-4", "d-5", "e-6"})
+	if msg != "bd: create (auto-commit) by bob [a-1, b-2, c-4, d-5, e-6]" {
+		t.Fatalf("unexpected capped message: %q", msg)
+	}
+
+	// Empty command/actor fallbacks
+	msg = formatDoltAutoCommitMessage("", "", nil)
+	if msg != "bd: write (auto-commit) by unknown" {
+		t.Fatalf("unexpected fallback message: %q", msg)
+	}
+}
+
+func TestIsDoltNothingToCommit(t *testing.T) {
+	if isDoltNothingToCommit(nil) {
+		t.Fatal("nil error should not be treated as nothing-to-commit")
+	}
+	if !isDoltNothingToCommit(errors.New("nothing to commit")) {
+		t.Fatal("expected nothing-to-commit to be detected")
+	}
+	if !isDoltNothingToCommit(errors.New("No changes to commit")) {
+		t.Fatal("expected no-changes-to-commit to be detected")
+	}
+	if isDoltNothingToCommit(errors.New("permission denied")) {
+		t.Fatal("unexpected classification")
+	}
+}