fix: keep the conversation when the agent list is re-polled

selectAgent cleared conversationId even when the agent hadn't changed, and the
60s inventory poll re-selects the persisted agent forever — so any message sent
a minute after the last one opened a fresh conversation. 27 of them yesterday,
four messages each. An empty curl body no longer counts as "no conversations".

surfaces/quickshell/services/Souveraine.qml

@@ -44,6 +44,19 @@ Singleton {
     property var agents: ({})
     property var agentList: Object.keys(agents)
     property string currentAgentId: ""
+    // Auto-resume: whenever the active agent is (re)established — shell start,
+    // reboot, agent switch — re-attach her latest server-persisted conversation
+    // so the next message continues the thread instead of minting a fresh one.
+    // Without this every shell reload starts amnesiac, and the shell reloads
+    // often (a deploy, a lock, a crash). The server is the source of truth here;
+    // the surface deliberately keeps no agent → conversation map of its own.
+    // Gated so it never clobbers a live turn or an already-attached thread.
+    onCurrentAgentIdChanged: {
+        if (root.currentAgentId.length > 0 && root.serverUp
+            && root.conversationId.length === 0 && !root.turnActive) {
+            root.resumeLatestConversation();
+        }
+    }
     property string conversationId: ""
     property bool turnActive: false
 
@@ -163,11 +176,30 @@ Singleton {
 
     function selectAgent(agentId) {
         if (!root.agents[agentId]) return false;
+        // Re-affirming the agent that is already active is a no-op, and it has
+        // to be. Ai.qml re-selects the persisted agent on every agentsRefreshed,
+        // and the inventory poll above fires that once a minute, forever. While
+        // this function cleared conversationId unconditionally, every message
+        // sent more than a minute after the previous one opened a NEW
+        // conversation and therefore arrived with no history at all.
+        //
+        // Measured on the phone 2026-07-31: 27 conversations for one agent in a
+        // day, all but two exactly four messages long — system prompt, ambient,
+        // user, reply. One exchange each. That is the whole of the "she doesn't
+        // remember what I just said" report, and it is not the turn loop: the
+        // server assembles history from session.messages correctly, and there
+        // was simply never more than one exchange in a session to assemble.
+        //
+        // Switching agents is a decision. Polling is not.
+        if (agentId === root.currentAgentId) return true;
         // A live turn belongs to the current conversation. Switching beneath
         // it would render one agent's response in another agent's surface.
         if (root.turnActive) return false;
-        root.currentAgentId = agentId;
+        // Clear before the id changes, so onCurrentAgentIdChanged observes an
+        // empty conversation and re-attaches the incoming agent's own latest
+        // thread rather than leaving her on a blank one.
         root.conversationId = "";
+        root.currentAgentId = agentId;
         return true;
     }
 
@@ -184,25 +216,40 @@ Singleton {
         property string agentId: ""
         stdout: StdioCollector {
             onStreamFinished: {
+                if (listConversations.agentId !== root.currentAgentId) return;
+                // Empty stdout is a FAILED request, not an empty agent: curl -sf
+                // writes nothing on 4xx/5xx. Conflating the two clears
+                // conversationId and hands the surface an empty transcript to
+                // render, so one transient hiccup wipes the visible thread and
+                // orphans the live one. Only a parsed response is authoritative.
+                if (text.length === 0) {
+                    console.log("[Souveraine] empty conversation list response — leaving current conversation in place");
+                    return;
+                }
                 let conversations = [];
                 try {
-                    conversations = text.length > 0 ? JSON.parse(text) : [];
+                    conversations = JSON.parse(text);
                 } catch (e) {
                     console.log("[Souveraine] Could not parse conversation list:", e);
+                    return;
                 }
-                if (listConversations.agentId !== root.currentAgentId) return;
                 if (conversations.length === 0) {
+                    // The server answered, and the answer is "none yet".
                     root.conversationId = "";
                     root.conversationResumed(root.currentAgentId, "", []);
                     return;
                 }
+                // Server sorts by updated_at descending — [0] is her latest.
                 root._loadConversation(listConversations.agentId, conversations[0].id);
             }
         }
         onExited: exitCode => {
+            // A failed list fetch is transient (server busy, network blip).
+            // Do NOT clear conversationId — that orphans the live thread and
+            // forces the next send to mint a fresh conversation. Log and leave
+            // state alone; the next refresh or /resume retries.
             if (exitCode !== 0 && listConversations.agentId === root.currentAgentId) {
-                root.conversationId = "";
+                console.log("[Souveraine] conversation list fetch failed (exit " + exitCode + ") — leaving current conversation in place");
-                root.conversationResumed(root.currentAgentId, "", []);
             }
         }
     }
@@ -213,21 +260,29 @@ Singleton {
         property string requestedConversationId: ""
         stdout: StdioCollector {
             onStreamFinished: {
+                if (loadConversation.agentId !== root.currentAgentId) return;
+                // Same rule as the list above: no body means the fetch failed.
+                // Attaching to the id anyway and announcing an empty transcript
+                // would blank the surface while claiming the thread is loaded.
+                if (text.length === 0) {
+                    console.log("[Souveraine] empty transcript response — leaving current conversation in place");
+                    return;
+                }
                 try {
-                    const messages = text.length > 0 ? JSON.parse(text) : [];
+                    const messages = JSON.parse(text);
-                    if (loadConversation.agentId !== root.currentAgentId) return;
                     root.conversationId = loadConversation.requestedConversationId;
                     root.conversationResumed(root.currentAgentId, root.conversationId, messages);
                 } catch (e) {
                     console.log("[Souveraine] Could not parse conversation transcript:", e);
-                    root.conversationResumed(root.currentAgentId, "", []);
                 }
             }
         }
         onExited: exitCode => {
+            // Transient failure (e.g. a 5xx on GET /messages). Don't clear —
+            // see listConversations.onExited. Leaving conversationId alone keeps
+            // an already-attached thread reachable instead of forcing a new one.
             if (exitCode !== 0 && loadConversation.agentId === root.currentAgentId) {
-                root.conversationId = "";
+                console.log("[Souveraine] conversation transcript fetch failed (exit " + exitCode + ") — leaving current conversation in place");
-                root.conversationResumed(root.currentAgentId, "", []);
             }
         }
     }