feat: accept --global on :report subcommands

Every `:report` subcommand now recognizes `--global` as a scope selector that limits the report to globally-configured properties, including in JSON form via `--global --format json`. Previously this combination was rejected because `--global` was treated as an info flag, conflicting with `--format`. The shared `common.ParseReportArgs` helper now returns a `ReportArgs` struct exposing the parsed scope; each Go and bash report selects a global-only flag map when scope is global, and skips per-app verification.

tests/unit/git_3.bats

@@ -831,3 +831,31 @@ teardown() {
   assert_failure
   assert_output_contains "--format flag cannot be specified when specifying an info flag"
 }
+
+@test "(git:report) --global" {
+  run /bin/bash -c "dokku git:report --global"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+  assert_output_contains "global git information"
+  assert_output_contains "Global deploy branch"
+}
+
+@test "(git:report) --global --format json" {
+  run /bin/bash -c "dokku git:report --global --format json | jq -e ."
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+
+  run /bin/bash -c "dokku git:report --global --format json | jq -r '.\"global-deploy-branch\"'"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+  assert_output "master"
+
+  run /bin/bash -c "dokku git:report --global --format json | jq -r 'has(\"deploy-branch\")'"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+  assert_output "false"
+}