fix: split report global keys into raw and computed across plugins

The `<plugin>-global-<property>` keys in `:report` output returned the resolved value with the built-in default substituted in, so external tooling could not distinguish a property that had been set globally to the default from one that had never been set. The bare keys for caddy, haproxy, and traefik global-only properties had the same shape. The `global-<property>` keys now hold the raw stored value and are empty when nothing has been set, and a new `computed-<property>` key holds the effective value used at runtime, falling back through the per-app value (where one exists), the global value, and the built-in default. The bare global-only keys for the three proxy plugins are removed in favor of the raw/computed pair. Closes #8631.

tests/unit/git_3.bats

@@ -887,7 +887,13 @@ teardown() {
   echo "output: $output"
   echo "status: $status"
   assert_success
-  assert_output "master"
+  assert_output ""
+
+  run /bin/bash -c "dokku git:report $TEST_APP --format json | jq -r '.\"computed-deploy-branch\"'"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
+  assert_output "main"
 
   run /bin/bash -c "dokku git:report $TEST_APP --format json | jq -e ."
   echo "output: $output"
@@ -925,6 +931,12 @@ teardown() {
   echo "output: $output"
   echo "status: $status"
   assert_success
+  assert_output ""
+
+  run /bin/bash -c "dokku git:report --global --format json | jq -r '.\"computed-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\")'"
@@ -937,5 +949,11 @@ teardown() {
   echo "output: $output"
   echo "status: $status"
   assert_success
+  assert_output ""
+
+  run /bin/bash -c "dokku git:report --global --git-computed-deploy-branch"
+  echo "output: $output"
+  echo "status: $status"
+  assert_success
   assert_output "master"
 }