fix: stabilize workspace transport and session persistence

apps/server/src/services/agent.rs

@@ -1,4 +1,5 @@
 use crate::*;
+use crate::services::utf8_stream::Utf8StreamDecoder;
 
 const DEFAULT_PTY_COLS: u16 = 120;
 const DEFAULT_PTY_ROWS: u16 = 30;
@@ -259,11 +260,41 @@ pub(crate) fn agent_start(
     std::thread::spawn(move || {
         let mut reader = reader;
         let mut buf = [0u8; 4096];
+        let mut decoder = Utf8StreamDecoder::new();
         loop {
             match reader.read(&mut buf) {
-                Ok(0) => break,
+                Ok(0) => {
+                    let text = decoder.finish();
+                    if !text.is_empty() {
+                        if let Ok(mut lifecycle_state) = lifecycle_fallback_state_out.lock() {
+                            if let Some((kind, source_event, data)) =
+                                fallback_agent_lifecycle_from_output(&mut lifecycle_state, &text)
+                            {
+                                emit_agent_lifecycle(
+                                    &app_handle,
+                                    &workspace_id_out,
+                                    &session_out,
+                                    kind,
+                                    source_event,
+                                    &data,
+                                );
+                            }
+                        }
+                        emit_agent(
+                            &app_handle,
+                            &workspace_id_out,
+                            &session_out,
+                            "stdout",
+                            &text,
+                        );
+                        let state: State<AppState> = state_handle.state();
+                        let _ =
+                            append_session_stream(state, &workspace_id_out, session_out_num, &text);
+                    }
+                    break;
+                }
                 Ok(n) => {
-                    let text = String::from_utf8_lossy(&buf[..n]).to_string();
+                    let text = decoder.push(&buf[..n]);
                     if text.is_empty() {
                         continue;
                     }

apps/server/src/services/mod.rs

@@ -5,6 +5,7 @@ pub(crate) mod filesystem;
 pub(crate) mod git;
 pub(crate) mod system;
 pub(crate) mod terminal;
+pub(crate) mod utf8_stream;
 pub(crate) mod workspace;
 pub(crate) mod workspace_runtime;
 pub(crate) mod workspace_watch;

apps/server/src/services/terminal.rs

@@ -1,4 +1,5 @@
 use crate::*;
+use crate::services::utf8_stream::Utf8StreamDecoder;
 
 const DEFAULT_PTY_COLS: u16 = 120;
 const DEFAULT_PTY_ROWS: u16 = 30;
@@ -83,11 +84,25 @@ pub(crate) fn terminal_create(
     std::thread::spawn(move || {
         let mut reader = reader;
         let mut buf = [0u8; 4096];
+        let mut decoder = Utf8StreamDecoder::new();
         loop {
             match reader.read(&mut buf) {
-                Ok(0) => break,
+                Ok(0) => {
+                    let text = decoder.finish();
+                    if !text.is_empty() {
+                        emit_terminal(&app_handle, &workspace_id_out, terminal_id, &text);
+                        let state: State<AppState> = state_handle.state();
+                        let _ = append_workspace_terminal_output(
+                            state,
+                            &workspace_id_out,
+                            terminal_id,
+                            &text,
+                        );
+                    }
+                    break;
+                }
                 Ok(n) => {
-                    let text = String::from_utf8_lossy(&buf[..n]).to_string();
+                    let text = decoder.push(&buf[..n]);
                     if text.is_empty() {
                         continue;
                     }

apps/server/src/services/utf8_stream.rs

@@ -0,0 +1,85 @@
+pub(crate) struct Utf8StreamDecoder {
+    pending: Vec<u8>,
+}
+
+impl Utf8StreamDecoder {
+    pub(crate) fn new() -> Self {
+        Self {
+            pending: Vec::new(),
+        }
+    }
+
+    pub(crate) fn push(&mut self, chunk: &[u8]) -> String {
+        if chunk.is_empty() {
+            return String::new();
+        }
+
+        self.pending.extend_from_slice(chunk);
+        let mut output = String::new();
+
+        loop {
+            match std::str::from_utf8(&self.pending) {
+                Ok(valid) => {
+                    output.push_str(valid);
+                    self.pending.clear();
+                    break;
+                }
+                Err(error) => {
+                    let valid_up_to = error.valid_up_to();
+                    if valid_up_to > 0 {
+                        let valid = std::str::from_utf8(&self.pending[..valid_up_to])
+                            .unwrap_or_default();
+                        output.push_str(valid);
+                        self.pending.drain(..valid_up_to);
+                    }
+
+                    match error.error_len() {
+                        Some(len) => {
+                            output.push('\u{FFFD}');
+                            self.pending.drain(..len);
+                        }
+                        None => break,
+                    }
+                }
+            }
+        }
+
+        output
+    }
+
+    pub(crate) fn finish(&mut self) -> String {
+        if self.pending.is_empty() {
+            return String::new();
+        }
+        let flushed = String::from_utf8_lossy(&self.pending).to_string();
+        self.pending.clear();
+        flushed
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::Utf8StreamDecoder;
+
+    #[test]
+    fn decodes_multibyte_characters_split_across_chunks() {
+        let mut decoder = Utf8StreamDecoder::new();
+
+        let first = decoder.push(&[0xE4, 0xBD]);
+        let second = decoder.push(&[0xA0, 0xE5, 0xA5, 0xBD]);
+        let flushed = decoder.finish();
+
+        assert_eq!(first, "");
+        assert_eq!(second, "你好");
+        assert_eq!(flushed, "");
+    }
+
+    #[test]
+    fn preserves_invalid_bytes_with_replacement_and_continues() {
+        let mut decoder = Utf8StreamDecoder::new();
+
+        let output = decoder.push(&[0x66, 0x80, 0x6F, 0x6F]);
+
+        assert_eq!(output, "f\u{FFFD}oo");
+    }
+}

apps/server/src/ws/protocol.rs

@@ -13,4 +13,40 @@ pub(crate) enum WsEnvelope {
 pub(crate) enum WsClientEnvelope {
     Ping { ts: i64 },
     Pong { ts: i64 },
+    AgentSend {
+        workspace_id: String,
+        session_id: String,
+        input: String,
+        append_newline: Option<bool>,
+        fencing_token: i64,
+    },
+    TerminalWrite {
+        workspace_id: String,
+        terminal_id: u64,
+        input: String,
+        fencing_token: i64,
+    },
+    TerminalResize {
+        workspace_id: String,
+        terminal_id: u64,
+        cols: u16,
+        rows: u16,
+        fencing_token: i64,
+    },
+    AgentResize {
+        workspace_id: String,
+        session_id: String,
+        cols: u16,
+        rows: u16,
+        fencing_token: i64,
+    },
+    SessionUpdate {
+        workspace_id: String,
+        session_id: u64,
+        patch: SessionPatch,
+        fencing_token: i64,
+    },
+    WorkspaceControllerHeartbeat {
+        workspace_id: String,
+    },
 }