fix: make /continue command work correctly

- Regenerate v2 SDK to include session.continue() method
- Update TUI to call session.continue() instead of session.prompt()
- Simplify server continue endpoint logic to avoid race conditions
- Cancel existing session state before starting new loop to prevent
  double abort errors

Closes sst#5150

Author: ariane-emory

packages/opencode/src/cli/cmd/tui/routes/session/index.tsx

@@ -394,17 +394,13 @@ export function Session() {
       keybind: "session_continue",
       category: "Session",
       onSelect: async (dialog) => {
-        const status = sync.data.session_status[route.sessionID]
-        if (status?.type !== "idle") await sdk.client.session.abort({ sessionID: route.sessionID }).catch(() => {})
-        
-        const result = await sdk.client.session.prompt({
+        const result = await sdk.client.session.continue({
           sessionID: route.sessionID,
         })
 
         if (result.data) {
           toBottom()
         } else {
-          // Show message that there's nothing to continue
           dialog.clear()
         }
       },

packages/opencode/src/server/server.ts

@@ -1358,45 +1358,19 @@ export namespace Server {
         async (c) => {
           const sessionID = c.req.valid("param").sessionID
 
-          // Check if session has an unfinished assistant message
+          // Check if there's a user message to continue from
           const msgs = await Session.messages({ sessionID })
-          let lastAssistant: MessageV2.Assistant | undefined
-          
-          for (let i = msgs.length - 1; i >= 0; i--) {
-            const msg = msgs[i]
-            if (msg.info.role === "assistant") {
-              lastAssistant = msg.info as MessageV2.Assistant
-              break
-            }
-          }
-          
-          // If no unfinished assistant message, return false
-          if (!lastAssistant || (lastAssistant.finish && !["tool-calls", "unknown"].includes(lastAssistant.finish))) {
+          const hasUserMessage = msgs.some((m) => m.info.role === "user")
+          if (!hasUserMessage) {
             return c.json(false)
           }
 
-          // Find the last user message to revert to
-          let lastUser: MessageV2.User | undefined
-          for (let i = msgs.length - 1; i >= 0; i--) {
-            const msg = msgs[i]
-            if (msg.info.role === "user") {
-              lastUser = msg.info as MessageV2.User
-              break
-            }
-          }
-          
-          if (!lastUser) {
-            return c.json(false)
-          }
+          // Cancel any existing session state to ensure clean start
+          SessionPrompt.cancel(sessionID)
 
-          // Revert unfinished assistant message
-          await SessionRevert.revert({
-            sessionID,
-            messageID: lastUser.id,
-          })
-          
-          // Start conversation loop to continue
-          await SessionPrompt.loop(sessionID)
+          // Start conversation loop - it will continue from where it left off
+          // The loop handles incomplete assistant messages automatically
+          SessionPrompt.loop(sessionID)
 
           return c.json(true)
         },