fix(bot-mode): local member replies carry from.source so cross-Desktop rooms attribute them

A group-room reply produced by a member local to the Desktop running the turn was
appended without `from.source`; when the shared room projection reached another
Desktop, that entry was indistinguishable from the reader's own same-named bot
(#94863 D3). Every member that knows its connection now stamps
`source: connectionLabel || connectionId` (groupMemberAuthor, used by both append
sites), and the `(you)` self-check in member prompts follows the same resolution
rule as routing.ts: a sourced line is "you" only when it matches the viewer's
connection, an unsourced line only for a local viewer.

Part of #94863 (D3 only; D2 realtime pull is a parked design decision).

apps/desktop/src/plugins/hermes-bots/group-membership.ts

@@ -7,7 +7,7 @@
 import { $botMeta, botFriendlyNames, botHandle, botMetaKey, botRosterKey } from './data'
 import { $groupChats, groupChatRoomKey } from './group-chat'
 import { botConnectionRoute, botRosterMeta, resolveBotConnectionRoute } from './routing'
-import type { BotMeta, GroupChat, GroupMember, RosterRow } from './types'
+import type { BotMeta, GroupChat, GroupMember, GroupMessageAuthor, RosterRow } from './types'
 
 /** Follow the authoritative room record for one async operation. Rename moves
  * the record wholesale (including legacy rooms without a roomId); disband
@@ -57,6 +57,17 @@ export function groupMemberKey(member: GroupMember): string {
   return member?.sourceScoped || member?.remoteSource ? botRosterKey(member) : member?.name
 }
 
+/** The `from` stamp for a member's appended reply. Every member that knows
+ *  its connection carries `source` — local ones included — so a reply
+ *  mirrored to another Desktop still names the machine it came from (#94863
+ *  D3: an unsourced `default` reply was indistinguishable from the reader's
+ *  own `default`). Only members without a connection stay bare. */
+export function groupMemberAuthor(member: GroupMember): GroupMessageAuthor {
+  const source = member.connectionLabel || member.connectionId
+
+  return { kind: 'member', name: member.name, ...(source ? { source } : {}) }
+}
+
 /** Marks a session key as thread-scoped. Pre-thread rooms stored ONE session
  *  per member under the bare `groupMemberKey`, and a source-qualified member
  *  key is itself `<connectionId>::<name>` — so the thread segment needs its

apps/desktop/src/plugins/hermes-bots/group-round-members.ts

@@ -10,7 +10,7 @@ import {
   updateGroupChat
 } from './group-chat'
 import type { GroupChatRoom } from './group-chat'
-import { groupMemberKey } from './group-membership'
+import { groupMemberAuthor, groupMemberKey } from './group-membership'
 import { buildGroupChatTurnPrompt, formatGroupDeltaLines } from './group-round-prompt'
 import { isGroupPassText, runGroupChatMemberTurn } from './group-turns'
 import type { Attachment, GroupMember, GroupMessage } from './types'
@@ -233,15 +233,7 @@ export async function runGroupRoundMember(
   if (reply !== null && !isGroupPassText(reply)) {
     appendGroupChatEntry(
       context.group,
-      {
-        kind: 'member',
-        name: member.name,
-        ...(member.remoteSource
-          ? {
-              source: member.connectionLabel || member.connectionId
-            }
-          : {})
-      },
+      groupMemberAuthor(member),
       reply,
       thread
     )

apps/desktop/src/plugins/hermes-bots/group-round-prompt.ts

@@ -71,11 +71,11 @@ function viewerNameOf(viewer: GroupChatLineViewer): string {
   return typeof viewer === 'string' ? viewer : viewer?.name || ''
 }
 
-/** Remote members stamp `from.source` as `connectionLabel || connectionId`.
- *  Only a remoteSource viewer exposes those tokens; a string or local member
- *  is unsourced so same-name remote lines fail open (no `(you)`). */
+/** Members stamp `from.source` as `connectionLabel || connectionId` (local
+ *  ones too, once they know their connection). A string viewer or a member
+ *  without a connection exposes no tokens. */
 function viewerConnectionSources(viewer: GroupChatLineViewer): string[] {
-  if (typeof viewer === 'string' || !viewer?.remoteSource) {
+  if (typeof viewer === 'string') {
     return []
   }
 
@@ -88,13 +88,14 @@ function isGroupChatSelf(from: GroupMessageAuthor, viewer: GroupChatLineViewer):
   }
 
   const speakerSource = from.source || ''
-  const viewerSources = viewerConnectionSources(viewer)
 
-  if (!speakerSource && viewerSources.length === 0) {
-    return true
+  // An unsourced same-name line is local by the room's resolution rule
+  // (routing.ts: no source ⇒ `!remoteSource`), so only a local viewer owns it.
+  if (!speakerSource) {
+    return typeof viewer === 'string' || !viewer?.remoteSource
   }
 
-  return Boolean(speakerSource) && viewerSources.includes(speakerSource)
+  return viewerConnectionSources(viewer).includes(speakerSource)
 }
 
 interface GroupChatTurnPromptInput {

apps/desktop/src/plugins/hermes-bots/group-rounds.test.ts

@@ -167,6 +167,26 @@ describe('routing', () => {
     expect(lines.some(line => line.startsWith('research:'))).toBe(true)
     expect(lines.some(line => line.startsWith('builder: On it'))).toBe(true)
   })
+
+  // #94863 D3: a LOCAL member's reply must carry from.source too, or the same
+  // entry mirrored to another Desktop reads as that Desktop's own same-named bot.
+  it('stamps a local member reply with its connection label and keeps (you) for that member only', async () => {
+    const room = await loadRoom({ turn: () => 'Central here.' })
+    const { formatGroupChatLine } = await import('./group-round-prompt')
+    const local: GroupMember = { connectionId: 'central', connectionLabel: 'Central', name: 'default', title: '' }
+
+    room.rounds.sendToGroupChat('Core', [local], '@hermes status?')
+    await settle(room, 'Core')
+
+    const reply = log(room, 'Core').find(entry => entry.from.kind === 'member')
+
+    expect(reply?.from).toEqual({ kind: 'member', name: 'default', source: 'Central' })
+    expect(formatGroupChatLine(reply as GroupMessage, local)).toContain('(you)')
+    // The same entry seen by the other machine's `default` is somebody else.
+    expect(
+      formatGroupChatLine(reply as GroupMessage, { connectionId: 'mbp', connectionLabel: 'MBP', name: 'default', remoteSource: true })
+    ).not.toContain('(you)')
+  })
 })
 
 describe('round lifecycle', () => {

apps/desktop/src/plugins/hermes-bots/group-turns.ts

@@ -14,6 +14,7 @@ import { $groupChats, $groupClarify, appendGroupChatEntry, updateGroupChat } fro
 import type { GroupChatRoom } from './group-chat'
 import {
   followGroupChat,
+  groupMemberAuthor,
   groupMemberKey,
   groupSessionKey,
   groupSessionOwner,
@@ -1172,15 +1173,7 @@ export async function harvestStrandedGroupReply(group: string, member: GroupMemb
       })
       appendGroupChatEntry(
         group,
-        {
-          kind: 'member',
-          name: member.name,
-          ...(member.remoteSource
-            ? {
-                source: member.connectionLabel || member.connectionId
-              }
-            : {})
-        },
+        groupMemberAuthor(member),
         reply,
         strandedThread
       )