Strip ANSI sequences from container logs for clean display.

PM2 and similar tools emit VT100 color codes that browsers hide only
partially, leaving artifacts like [32m between table columns. Strip CSI/OSC
escapes when formatting log lines, and harden Docker multiplex demux on the
server so frames are not mis-parsed as text.

server/handlers/logs.js

@@ -8,9 +8,12 @@ import logger from '../utils/logger.js'
 
 /**
  * Incremental demux of docker log multiplex protocol.
+ * Frame: 1 byte stream type (0–2) + 3 zero bytes + 4 byte BE size + payload.
  */
 function createServerDemuxer() {
   let pending = Buffer.alloc(0)
+  /** Once we see a valid mux frame, stay in mux mode for the stream. */
+  let muxMode = null // null | true | false
 
   return {
     /**
@@ -21,15 +24,54 @@ function createServerDemuxer() {
       pending = Buffer.concat([pending, chunk])
       const out = []
 
-      // Non-muxed (raw text) — if first byte isn't 0-2 and we have data
-      if (pending.length && pending[0] > 2) {
-        out.push(pending)
-        pending = Buffer.alloc(0)
+      if (muxMode === false) {
+        if (pending.length) {
+          out.push(pending)
+          pending = Buffer.alloc(0)
+        }
+        return out
+      }
+
+      // Detect mode from first full frame or non-mux text
+      if (muxMode === null && pending.length >= 1) {
+        const b0 = pending[0]
+        if (b0 > 2) {
+          muxMode = false
+          out.push(pending)
+          pending = Buffer.alloc(0)
+          return out
+        }
+        // Need header to confirm
+        if (pending.length >= 8) {
+          const size = pending.readUInt32BE(4)
+          // Plausible frame: type 0-2, zeros in 1-3, reasonable size
+          const zerosOk = pending[1] === 0 && pending[2] === 0 && pending[3] === 0
+          if (b0 <= 2 && zerosOk && size > 0 && size < 16 * 1024 * 1024) {
+            muxMode = true
+          } else if (b0 <= 2 && !zerosOk) {
+            // Not mux — treat as raw (e.g. TTY)
+            muxMode = false
+            out.push(pending)
+            pending = Buffer.alloc(0)
+            return out
+          }
+        }
+      }
+
+      if (muxMode !== true) {
+        // Wait for more bytes to decide, or emit if clearly not mux
         return out
       }
 
       while (pending.length >= 8) {
         const size = pending.readUInt32BE(4)
+        if (size < 0 || size > 16 * 1024 * 1024) {
+          // Corrupt header — fall back to raw remainder
+          out.push(pending)
+          pending = Buffer.alloc(0)
+          muxMode = false
+          break
+        }
         if (pending.length < 8 + size) break
         out.push(pending.subarray(8, 8 + size))
         pending = pending.subarray(8 + size)