fix(tmux): pick per-instance ports and restore pane cleanup

.config/fish/functions/c.fish

@@ -1,7 +1,9 @@
 function c --wraps=opencode --description 'opencode (auto-starts tmux for visual subagent panes)'
+    set -l port (python -c 'import socket; s=socket.socket(); s.bind(("127.0.0.1", 0)); print(s.getsockname()[1]); s.close()')
+
     if not set -q TMUX
-        tmux new-session opencode $argv
+        tmux new-session opencode --port $port $argv
     else
-        opencode $argv
+        opencode --port $port $argv
     end
 end

.config/fish/functions/cc.fish

@@ -1,7 +1,9 @@
 function cc --wraps='opencode --continue' --description 'opencode --continue (auto-starts tmux for visual subagent panes)'
+    set -l port (python -c 'import socket; s=socket.socket(); s.bind(("127.0.0.1", 0)); print(s.getsockname()[1]); s.close()')
+
     if not set -q TMUX
-        tmux new-session opencode --continue $argv
+        tmux new-session opencode --port $port --continue $argv
     else
-        opencode --continue $argv
+        opencode --port $port --continue $argv
     end
 end

.config/opencode/plugins/tmux-panes.ts

@@ -1,6 +1,5 @@
 import type { Plugin } from "@opencode-ai/plugin"
 import { spawn } from "bun"
-import { appendFileSync } from "fs"
 
 /**
  * tmux-panes plugin
@@ -14,14 +13,8 @@ import { appendFileSync } from "fs"
  *   - Panes close automatically when subagent sessions end
  *
  * Only activates when running inside a tmux session (TMUX env var is set).
- *
- * Debug log: /tmp/opencode-tmux-debug.log
  */
 
-const DEBUG_LOG = "/tmp/opencode-tmux-debug.log"
-const log = (msg: string) =>
-	appendFileSync(DEBUG_LOG, `[${new Date().toISOString()}] ${msg}\n`)
-
 const isInsideTmux = () => Boolean(process.env.TMUX)
 const getCurrentPaneId = () => process.env.TMUX_PANE
 
@@ -31,7 +24,6 @@ const plugin: Plugin = async (ctx) => {
 	const sessions = new Map<string, string>() // sessionId → tmux paneId
 	const sourcePaneId = getCurrentPaneId()
 	const serverUrl = (ctx.serverUrl?.toString() ?? "").replace(/\/$/, "")
-	log(`plugin init — serverUrl=${serverUrl} sourcePaneId=${sourcePaneId}`)
 
 	// Ordered list of pane IDs in the right column.
 	// Empty = no right column yet; length > 0 = right column exists.
@@ -47,11 +39,7 @@ const plugin: Plugin = async (ctx) => {
 			const sessionId: string = info.id
 			if (sessions.has(sessionId)) return
 
-				// Wrap the attach command: on failure, show the error and keep the
+			const cmd = `opencode attach ${serverUrl} --session ${sessionId}`
-			// pane open for 30 s so we can read it before it disappears.
-			const attachCmd = `opencode attach ${serverUrl} --session ${sessionId}`
-			const cmd = `bash -c '${attachCmd}; echo "--- exit: $? ---" >> ${DEBUG_LOG}; sleep 30'`
-			log(`spawning pane — cmd: ${attachCmd}`)
 
 				let args: string[]
 				if (rightColumnPanes.length === 0) {
@@ -89,7 +77,6 @@ const plugin: Plugin = async (ctx) => {
 				const proc = spawn(args, { stdout: "pipe", stderr: "pipe" })
 				const paneId = (await new Response(proc.stdout).text()).trim()
 				const exitCode = await proc.exited
-			log(`split-window exit=${exitCode} paneId=${paneId}`)
 				if (exitCode === 0 && paneId) {
 					sessions.set(sessionId, paneId)
 					rightColumnPanes.push(paneId)