Fix config sync for perfomance mode and timeouts (#4908)

## Changes

Use the same logic for server-side defaults as in resources.yml logic.

I have a PR that updates `config-remote-sync` to use `resources.yml`,
but it's not yet ready to merge
#4677



## Why
<!-- Why are these changes needed? Provide the context that the reviewer
might be missing.
For example, were there any decisions behind the change that are not
reflected in the code itself? -->

Changes in performance mode were incorrectly ignored previously

## Tests
<!-- How have you tested the changes? -->

<!-- If your PR needs to be included in the release notes for next
release,
add a separate entry in NEXT_CHANGELOG.md as part of your PR. -->

Author: ilyakuz-db

acceptance/bundle/config-remote-sync/config_edits/output.txt

@@ -26,6 +26,7 @@ Resource: resources.jobs.my_job
   email_notifications.on_failure[0]: replace
   max_concurrent_runs: replace
   tags['env']: remove
+  timeout_seconds: remove
 
 
 
@@ -41,15 +42,16 @@ Resource: resources.jobs.my_job
 +              - remote-failure@example.com
            parameters:
              - name: catalog
-@@ -35,7 +35,6 @@
+@@ -35,8 +35,6 @@
                unit: DAYS
            tags:
 -            env: config-production
              team: data-team
 -          max_concurrent_runs: 3
+-          timeout_seconds: 3600
 +          max_concurrent_runs: 5
-           timeout_seconds: 3600
            environments:
+             - environment_key: default
 
 >>> [CLI] bundle destroy --auto-approve
 The following resources will be deleted:

bundle/configsync/defaults.go

@@ -97,12 +97,20 @@ var serverSideDefaults = map[string]any{
 	"resources.pipelines.*.continuous": false,
 }
 
-func shouldSkipField(path string, value any) bool {
+// shouldSkipField checks if a field should be skipped in change detection.
+// When hasConfigValue is true (field is set in config or saved state), only
+// "always skip" fields are skipped. Backend defaults are only skipped when the
+// field is not in config/state, matching the behavior of shouldSkipBackendDefault
+// in the direct deployment engine.
+func shouldSkipField(path string, value any, hasConfigValue bool) bool {
 	for pattern, expected := range serverSideDefaults {
 		if matchPattern(pattern, path) {
 			if _, ok := expected.(skipAlways); ok {
 				return true
 			}
+			if hasConfigValue {
+				return false
+			}
 			if _, ok := expected.(skipIfZeroOrNil); ok {
 				return value == nil || value == int64(0)
 			}

bundle/configsync/diff.go

@@ -70,7 +70,7 @@ func filterEntityDefaults(basePath string, value any) any {
 	for key, val := range m {
 		fieldPath := basePath + "." + key
 
-		if shouldSkipField(fieldPath, val) {
+		if shouldSkipField(fieldPath, val, false) {
 			continue
 		}
 
@@ -91,7 +91,7 @@ func convertChangeDesc(path string, cd *deployplan.ChangeDesc) (*ConfigChangeDes
 		return nil, fmt.Errorf("failed to normalize remote value: %w", err)
 	}
 
-	if shouldSkipField(path, normalizedValue) {
+	if shouldSkipField(path, normalizedValue, hasConfigValue) {
 		return &ConfigChangeDesc{
 			Operation: OperationSkip,
 		}, nil