lock surface: restore redacted chat on unlock + announce replies

Redacted messages stayed '[content hidden until unlock]' forever — nothing
restored them on unlock. Redaction now records the message and unlock
restores content from rawContent. Turns finishing while locked are also
redacted and surfaced. New LockAgentCard shows a one-line preview of
replies that landed during the lock window on the lock glance, like a
notification; body stays hidden until unlock.

sessiond auth: getpwuid_r buffer is u8 with a c_char cast so it compiles
on aarch64 (c_char = u8 there) and x86 (c_char = i8).

src/sessiond/auth.rs

@@ -158,9 +158,18 @@ pub fn session_user() -> Result<String, String> {
     unsafe {
         let uid = libc::getuid();
         let mut pwd: libc::passwd = std::mem::zeroed();
-        let mut buf = [0i8; 1024];
+        let mut buf = [0u8; 1024];
         let mut result: *mut libc::passwd = std::ptr::null_mut();
-        let rc = libc::getpwuid_r(uid, &mut pwd, buf.as_mut_ptr(), buf.len(), &mut result);
+        // libc's `c_char` is i8 on some targets and u8 on others (aarch64),
+        // so the buffer is `u8` and we cast through `c_char` to satisfy
+        // whichever signature the target's libc crate exposes.
+        let rc = libc::getpwuid_r(
+            uid,
+            &mut pwd,
+            buf.as_mut_ptr() as *mut libc::c_char,
+            buf.len(),
+            &mut result,
+        );
         if rc != 0 || result.is_null() {
             return Err(format!("getpwuid_r failed for uid {uid}"));
         }

surfaces/quickshell/deploy.sh

@@ -73,6 +73,7 @@ modules/common/panels/lock/LockScreen.qml souveraine/modules/common/panels/lock/
 modules/ii/lock/Lock.qml                  souveraine/modules/ii/lock/Lock.qml
 modules/ii/lock/TouchLockSurface.qml      souveraine/modules/ii/lock/TouchLockSurface.qml
 modules/souveraine/lock/LockMediaCard.qml  souveraine/modules/souveraine/lock/LockMediaCard.qml
+modules/souveraine/lock/LockAgentCard.qml  souveraine/modules/souveraine/lock/LockAgentCard.qml
 modules/souveraine/lock/LockSurfaceHost.qml souveraine/modules/souveraine/lock/LockSurfaceHost.qml
 modules/souveraine/lock/qmldir          souveraine/modules/souveraine/lock/qmldir
 modules/souveraine/navigation/SystemGestureRail.qml souveraine/modules/souveraine/navigation/SystemGestureRail.qml

surfaces/quickshell/modules/souveraine/lock/LockAgentCard.qml

@@ -0,0 +1,77 @@
+// Ambient "the agent replied" card. While the session is locked, personal-tier
+// agent output is redacted in the chat (Ai.qml). This surface announces that a
+// reply landed — one-line preview only, never the body — so the lock screen
+// behaves like a notification: you see that she answered, and the full text
+// restores in the chat on unlock. See SESSION-TRUST-ARCHITECTURE.md (ambient
+// output is safe on the lock surface; personal is not).
+import QtQuick
+import QtQuick.Layouts
+import qs.services
+
+Item {
+    id: root
+
+    property var previews: []
+
+    implicitHeight: card.visible ? card.implicitHeight : 0
+    visible: previews.length > 0
+
+    function refresh() {
+        root.previews = Ai.redactedPreviews();
+    }
+
+    Connections {
+        target: Ai
+        function onRedactedMessagesChanged() { root.refresh() }
+    }
+    Connections {
+        target: GlobalStates
+        // Repopulate on lock, clear on unlock (the chat takes over).
+        function onScreenLockedChanged() {
+            if (GlobalStates.screenLocked) root.refresh();
+            else root.previews = [];
+        }
+    }
+
+    Rectangle {
+        id: card
+        anchors.fill: parent
+        visible: root.previews.length > 0
+        radius: 16
+        color: "#22000000"
+        border.color: "#33ffffff"
+        border.width: 1
+        implicitHeight: layout.implicitHeight + 24
+
+        ColumnLayout {
+            id: layout
+            anchors.left: parent.left
+            anchors.right: parent.right
+            anchors.verticalCenter: parent.verticalCenter
+            anchors.margins: 12
+            spacing: 4
+
+            Text {
+                Layout.fillWidth: true
+                text: qsTr("Souveraine replied while locked")
+                color: "#ccffffff"
+                font.pixelSize: 12
+                font.weight: Font.DemiBold
+                elide: Text.ElideRight
+            }
+
+            Repeater {
+                model: root.previews.slice(0, 3)
+                delegate: Text {
+                    required property string modelData
+                    Layout.fillWidth: true
+                    text: "• " + modelData
+                    color: "#e6ffffff"
+                    font.pixelSize: 14
+                    elide: Text.ElideRight
+                    maximumLineCount: 1
+                }
+            }
+        }
+    }
+}

surfaces/quickshell/modules/souveraine/lock/LockSurfaceHost.qml

@@ -65,5 +65,11 @@ Item {
             Layout.alignment: Qt.AlignHCenter
             Layout.fillWidth: true
         }
+
+        LockAgentCard {
+            Layout.topMargin: root.compact ? 6 : 10
+            Layout.alignment: Qt.AlignHCenter
+            Layout.fillWidth: true
+        }
     }
 }

surfaces/quickshell/modules/souveraine/lock/qmldir

@@ -1,3 +1,4 @@
 module qs.modules.souveraine.lock
 LockMediaCard 1.0 LockMediaCard.qml
 LockSurfaceHost 1.0 LockSurfaceHost.qml
+LockAgentCard 1.0 LockAgentCard.qml

surfaces/quickshell/services/Ai.qml

@@ -131,20 +131,71 @@ Singleton {
     // raw content is preserved in the message's rawContent so it can be
     // shown again after unlock (the message stays in history), but the
     // displayed content is cleared.
+    //
+    // The redaction is reversible: every message whose content we replaced
+    // with the placeholder is recorded in `redactedOnLock`, and on unlock
+    // its content is restored from `rawContent` (the streaming message too,
+    // if it is still in flight). A finished message redacted at lock then
+    // surfaced on the lock screen counts as "delivered" and is restored
+    // normally on unlock; one that never surfaced stays for the chat to
+    // replay once unlocked.
+    property var redactedOnLock: []
+
+    function _redactMessage(msg) {
+        if (!msg || msg.content.length === 0) return;
+        if (msg.content === Translation.tr("[content hidden until unlock]")) return;
+        msg.rawContent = msg.content;
+        msg.content = Translation.tr("[content hidden until unlock]");
+        if (!root.redactedOnLock.includes(msg)) {
+            root.redactedOnLock = [...root.redactedOnLock, msg];
+        }
+        root.redactedMessagesChanged();
+    }
+
+    function _restoreRedacted() {
+        if (root.redactedOnLock.length === 0) return;
+        for (const msg of root.redactedOnLock) {
+            if (msg && msg.rawContent && msg.rawContent.length > 0) {
+                msg.content = msg.rawContent;
+            }
+        }
+        root.redactedOnLock = [];
+        root.redactedMessagesChanged();
+    }
+
+    // Messages redacted while locked, newest first, for the lock surface to
+    // surface as ambient notifications. Strips to a one-line preview — the
+    // lock screen shows "the agent replied", not the personal-tier body.
+    function redactedPreviews() {
+        return root.redactedOnLock
+            .filter(m => m && m.rawContent && m.rawContent.length > 0 && m.role === "assistant")
+            .map(m => {
+                const firstLine = m.rawContent.split("\n").find(l => l.trim().length > 0) || "";
+                return firstLine.slice(0, 80);
+            })
+            .reverse();
+    }
+
+    signal redactedMessagesChanged()
+
     Connections {
         target: GlobalStates
         function onScreenLockedChanged() {
-            if (!GlobalStates.screenLocked) return;
-            if (!root.streamingMessage) return;
-            // Lock fired mid-stream. Redact the displayed content.
-            // rawContent preserves the actual response for post-unlock.
-            if (root.streamingMessage.content.length > 0) {
-                root.streamingMessage.content = Translation.tr("[content hidden until unlock]");
-                console.log("[ai] lock fired during stream — redacted personal output");
+            if (GlobalStates.screenLocked) {
+                // Lock fired mid-stream — redact the in-flight content.
+                if (root.streamingMessage) {
+                    root._redactMessage(root.streamingMessage);
+                    console.log("[ai] lock fired during stream — redacted personal output");
+                }
+            } else {
+                // Unlock: restore every message we hid, so the chat shows
+                // what actually came back rather than lingering placeholders.
+                root._restoreRedacted();
             }
         }
     }
 
+
     // ── Streaming message shaping ────────────────────────────────────────
     property AiMessageData streamingMessage
     property bool inThinkBlock: false
@@ -171,6 +222,12 @@ Singleton {
         }
         root.streamingMessage.thinking = false;
         root.streamingMessage.done = true;
+        // If the turn finished while the session is locked, the finished
+        // assistant message is personal-tier output the user hasn't seen —
+        // redact it for the chat view and let the lock surface announce it.
+        if (GlobalStates.screenLocked && root.streamingMessage.content.length > 0) {
+            root._redactMessage(root.streamingMessage);
+        }
         if (root.postResponseHook) {
             root.postResponseHook();
             root.postResponseHook = null;