fix(web): normalize non-sidechain text-only array user output as user message (#409)

The CLI wraps array-content user messages as agent output because
isExternalUserMessage rejects non-string content. On the web side,
detect text-only arrays in non-sidechain user output and emit them as
role:'user' so they display in the user lane.

Also handle sidechain user messages with mixed array content (e.g.
tool_result + text) by extracting text parts into a sidechain block.

Closes #407's original scope on top of the #402 base.

via [HAPI](https://hapi.run)

Co-authored-by: HAPI <noreply@hapi.run>

web/src/chat/normalize.test.ts

@@ -319,4 +319,57 @@ describe('normalizeDecryptedMessage', () => {
             parentUUID: null
         })
     })
+
+    it('normalizes non-sidechain text-only array-content user output as user message', () => {
+        const message = makeMessage({
+            role: 'agent',
+            content: {
+                type: 'output',
+                data: {
+                    type: 'user',
+                    uuid: 'u5',
+                    isSidechain: false,
+                    message: { content: [{ type: 'text', text: 'Regular user message' }] }
+                }
+            }
+        })
+
+        const normalized = normalizeDecryptedMessage(message)
+
+        expect(normalized).toMatchObject({
+            role: 'user',
+            isSidechain: false,
+            content: { type: 'text', text: 'Regular user message' }
+        })
+    })
+
+    it('treats sidechain user output with mixed tool_result + text array as sidechain', () => {
+        const message = makeMessage({
+            role: 'agent',
+            content: {
+                type: 'output',
+                data: {
+                    type: 'user',
+                    uuid: 'u6',
+                    isSidechain: true,
+                    message: { content: [
+                        { type: 'tool_result', tool_use_id: 'tc-1', content: 'result' },
+                        { type: 'text', text: 'Some subagent text' }
+                    ] }
+                }
+            }
+        })
+
+        const normalized = normalizeDecryptedMessage(message)
+
+        expect(normalized).toMatchObject({
+            role: 'agent',
+            isSidechain: true,
+        })
+        if (normalized?.role !== 'agent') throw new Error('Expected agent')
+        expect(normalized.content[0]).toMatchObject({
+            type: 'sidechain',
+            prompt: 'Some subagent text'
+        })
+    })
 })

web/src/chat/normalizeAgent.ts

@@ -159,6 +159,27 @@ function normalizeUserOutput(
         }
     }
 
+    // Non-sidechain array content that is all text blocks — these are real
+    // user messages that the CLI wrapped as agent output because
+    // isExternalUserMessage rejects array content. Emit as role:'user' so
+    // they display in the user lane.
+    if (!isSidechain && Array.isArray(messageContent)) {
+        const textParts = messageContent
+            .filter((b: unknown) => isObject(b) && b.type === 'text' && typeof b.text === 'string')
+            .map((b: Record<string, unknown>) => b.text as string)
+        if (textParts.length > 0 && textParts.length === messageContent.length) {
+            return {
+                id: messageId,
+                localId,
+                createdAt,
+                role: 'user',
+                isSidechain: false,
+                content: { type: 'text', text: textParts.join('\n\n') },
+                meta
+            }
+        }
+    }
+
     const blocks: NormalizedAgentContent[] = []
 
     if (Array.isArray(messageContent)) {