fix(chat): preserve attachment references from JSON RPC results (#1210)

Co-authored-by: M57 <41645758+Hy4ri@users.noreply.github.com>

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatServerMessageMapper.kt

@@ -196,7 +196,14 @@ internal fun mapServerMessages(
             return@forEachIndexed
         }
 
-        var finalContent = rawContent
+        // Context-reference preprocessing can persist model-facing attachment
+        // contents after the user's text. A cold reload / second device has no
+        // optimistic local bubble to hide that enriched REST representation,
+        // so project the producer-owned suffix out at hydration time too.
+        // Keep the actual @file:/@image: token here: unlike the dedupe path,
+        // REST-only hydration cannot prove that reference was not user-authored.
+        var finalContent =
+            if (role == MessageRole.USER) stripGatewayAttachedContext(rawContent) else rawContent
         var attachments: List<Attachment>? = null
         if (role == MessageRole.ASSISTANT && rawContent.contains("MEDIA:")) {
             val items = HostMediaExtractor.extract(rawContent)

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatTranscriptMerge.kt

@@ -6,6 +6,38 @@ import kotlinx.serialization.json.JsonElement
 import kotlinx.serialization.json.JsonObject
 import kotlinx.serialization.json.JsonPrimitive
 
+private val ATTACHED_CONTEXT_MARKER_RE =
+    Regex("""(?:^|\n)--- Attached Context ---\s*\n""")
+
+private val CONTEXT_REF_RE =
+    Regex(
+        """@(file|folder|url|image|tool|terminal):(?:"[^"\n]+"|'[^'\n]+'|`[^`\n]+`|\S+)""",
+    )
+
+/**
+ * Remove a gateway-generated `--- Attached Context ---` suffix while
+ * preserving the user-authored portion of the message.
+ *
+ * The marker itself is plain text a user can legitimately type, so do not
+ * treat it as a producer boundary unless the suffix also contains a context
+ * reference of the shape emitted by the gateway.
+ *
+ * Unlike [stripAttachmentRefLines], this intentionally keeps `@file:` /
+ * `@image:` references in the visible text. REST-only hydration has no local
+ * optimistic bubble proving those references were injected by Mobile, and
+ * users may have authored context references themselves.
+ */
+internal fun stripGatewayAttachedContext(content: String): String {
+    val marker = ATTACHED_CONTEXT_MARKER_RE.find(content) ?: return content
+    val attachedContext = content.substring(marker.range.last + 1)
+
+    if (!CONTEXT_REF_RE.containsMatchIn(attachedContext)) {
+        return content
+    }
+
+    return content.substring(0, marker.range.first).trimEnd()
+}
+
 /**
  * Canonical comparison key for a tool message's result payload.
  *
@@ -127,7 +159,7 @@ internal fun sameLogicalMessage(
  * run_agent). Blank lines left behind are dropped too.
  */
 internal fun stripAttachmentRefLines(content: String): String =
-    content
+    stripGatewayAttachedContext(content)
         .lines()
         .map { it.trim() }
         .filterNot { line ->

app/src/main/java/com/m57/hermescontrol/ui/chat/ChatViewModel.kt

@@ -1877,7 +1877,7 @@ class ChatViewModel(
                                             "filename" to attachment.name,
                                             "ext" to attachment.fileExtension,
                                         ),
-                                )
+                                ).let { if (it is JsonElement) it.toAny() else it }
                             if (result != null) {
                                 @Suppress("UNCHECKED_CAST")
                                 val ok = (result as? Map<String, Any?>)?.get("attached") as? Boolean
@@ -1897,7 +1897,10 @@ class ChatViewModel(
                                         "data_url" to "data:${attachment.mimeType};base64,$b64",
                                         "name" to attachment.name,
                                     ),
-                            )?.let { result ->
+                            )?.let { response ->
+                                // request() returns raw JsonElement values; normalize before reading Kotlin types.
+                                val result = if (response is JsonElement) response.toAny() else response
+
                                 @Suppress("UNCHECKED_CAST")
                                 val refText =
                                     (result as? Map<String, Any?>)?.get("ref_text") as? String