fix: show single success emoji in completion notifications (#70)

## Summary

- Remove the duplicate ✅ from the default **Status** field on pipeline
success notifications
- Keep the checkmark in the message header (`✅ *Pipeline completed
successfully*`) so success is still visually indicated once in the
message body
- Applies to both the default complete message and map-based custom
messages that include the `status` field

Closes #66

## Test plan

- [x] `./gradlew test --tests
"nextflow.slack.SlackMessageBuilderTest.should build workflow complete
message"`
- [x] `./gradlew test --tests
"nextflow.slack.SlackMessageBuilderTest.should use map-based custom
complete message with selective fields"`
- [x] `./gradlew test --tests
"nextflow.slack.SlackMessageBuilderTest.should use custom complete
message template"`


Made with [Cursor](https://cursor.com)

---------

Co-authored-by: Cursor <cursoragent@cursor.com>

Author: adamrtalbot

src/main/groovy/nextflow/slack/SlackMessageBuilder.groovy

@@ -311,7 +311,7 @@ class SlackMessageBuilder {
             fields << createMarkdownField('Duration', duration.toString())
         }
         if (shouldIncludeField(includeFields, 'status')) {
-            fields << createMarkdownField('Status', '✅ Success')
+            fields << createMarkdownField('Status', getStatusText('completed'))
         }
 
         // Add resource usage if configured (via includeResourceUsage or includeFields)
@@ -373,7 +373,7 @@ class SlackMessageBuilder {
             fields << createMarkdownField('Duration', duration.toString())
         }
         if (shouldIncludeField(includeFields, 'status')) {
-            fields << createMarkdownField('Status', '❌ Failed')
+            fields << createMarkdownField('Status', getStatusText('failed'))
         }
 
         if (shouldIncludeField(includeFields, 'failedProcess') && errorRecord) {
@@ -487,7 +487,7 @@ class SlackMessageBuilder {
                 fields << createMarkdownField('Duration', duration.toString())
             }
             if (includeFields.contains('status')) {
-                fields << createMarkdownField('Status', getStatusEmoji(status))
+                fields << createMarkdownField('Status', getStatusText(status))
             }
             if (includeFields.contains('failedProcess') && errorRecord) {
                 def processName = errorRecord.get('process')
@@ -566,16 +566,16 @@ class SlackMessageBuilder {
     }
 
     /**
-     * Get status emoji
+     * Get status text for the Status field (emoji-free; header carries the emoji).
      */
-    private static String getStatusEmoji(String status) {
+    private static String getStatusText(String status) {
         switch (status) {
             case 'started':
-                return '🚀 Running'
+                return 'Running'
             case 'completed':
-                return '✅ Success'
+                return 'Success'
             case 'failed':
-                return '❌ Failed'
+                return 'Failed'
             default:
                 return 'Unknown'
         }

src/test/groovy/nextflow/slack/SlackMessageBuilderTest.groovy

@@ -879,4 +879,96 @@ class SlackMessageBuilderTest extends Specification {
         !fields.find { it.text.contains('Duration') }
         !fields.find { it.text.contains('Status') }
     }
+
+    def 'status field should be text-only in default complete message'() {
+        given:
+        def metadata = Mock(WorkflowMetadata)
+        metadata.scriptName >> 'test-workflow.nf'
+        metadata.duration >> Duration.of('1h')
+        metadata.stats >> null
+        session.workflowMetadata >> metadata
+
+        when:
+        def message = messageBuilder.buildWorkflowCompleteMessage()
+        def json = new JsonSlurper().parseText(message)
+
+        then:
+        def headerBlock = json.blocks.find { it.type == 'section' && it.text?.text?.contains('Pipeline completed successfully') }
+        headerBlock.text.text.contains('✅')
+        statusFieldValue(json) == 'Success'
+        !statusFieldValue(json).contains('✅')
+    }
+
+    def 'status field should be text-only in default error message'() {
+        given:
+        def errorSession = Mock(Session)
+        def metadata = Mock(WorkflowMetadata)
+        metadata.scriptName >> 'test-workflow.nf'
+        metadata.duration >> Duration.of('30m')
+        metadata.errorMessage >> 'Process failed'
+        errorSession.workflowMetadata >> metadata
+        errorSession.runName >> 'test-run'
+        def builder = new SlackMessageBuilder(config, errorSession)
+
+        when:
+        def message = builder.buildWorkflowErrorMessage(null)
+        def json = new JsonSlurper().parseText(message)
+
+        then:
+        def headerBlock = json.blocks.find { it.type == 'section' && it.text?.text?.contains('Pipeline failed') }
+        headerBlock.text.text.contains('❌')
+        statusFieldValue(json) == 'Failed'
+        !statusFieldValue(json).contains('❌')
+    }
+
+    def 'status field should be text-only in map-based custom messages'() {
+        given:
+        def metadata = Mock(WorkflowMetadata)
+        metadata.scriptName >> 'test-workflow.nf'
+        metadata.duration >> Duration.of('1h')
+        session.workflowMetadata >> metadata
+
+        def startConfig = new SlackConfig([
+            enabled: true,
+            webhook: 'https://hooks.slack.com/services/TEST/TEST/TEST',
+            onStart: [
+                enabled: true,
+                message: [text: '🚀 *Starting*', includeFields: ['status']]
+            ]
+        ])
+        def completeConfig = new SlackConfig([
+            enabled: true,
+            webhook: 'https://hooks.slack.com/services/TEST/TEST/TEST',
+            onComplete: [
+                enabled: true,
+                message: [text: '✅ *Done*', includeFields: ['status']]
+            ]
+        ])
+        def errorConfig = new SlackConfig([
+            enabled: true,
+            webhook: 'https://hooks.slack.com/services/TEST/TEST/TEST',
+            onError: [
+                enabled: true,
+                message: [text: '❌ *Boom*', includeFields: ['status']]
+            ]
+        ])
+        def errorSession = Mock(Session)
+        def errorMetadata = Mock(WorkflowMetadata)
+        errorMetadata.scriptName >> 'test-workflow.nf'
+        errorMetadata.duration >> Duration.of('30m')
+        errorMetadata.errorMessage >> 'failed'
+        errorSession.workflowMetadata >> errorMetadata
+        errorSession.runName >> 'test-run'
+
+        expect:
+        statusFieldValue(new JsonSlurper().parseText(new SlackMessageBuilder(startConfig, session).buildWorkflowStartMessage())) == 'Running'
+        statusFieldValue(new JsonSlurper().parseText(new SlackMessageBuilder(completeConfig, session).buildWorkflowCompleteMessage())) == 'Success'
+        statusFieldValue(new JsonSlurper().parseText(new SlackMessageBuilder(errorConfig, errorSession).buildWorkflowErrorMessage(null))) == 'Failed'
+    }
+
+    private static String statusFieldValue(json) {
+        def fieldsBlock = json.blocks.find { it.type == 'section' && it.fields }
+        def statusField = fieldsBlock?.fields?.find { it.text.startsWith('*Status*') }
+        return statusField?.text?.replace('*Status*\n', '') ?: ''
+    }
 }