Fix URL detector truncating wrapped URLs arriving in separate PTY chunks

The PTY may deliver a long URL across multiple chunks with enough delay
that the debounce fires between them, emitting a truncated URL. Fixed by:
1. Stripping trailing empty strings from split (artifact of trailing \n)
2. Deferring emission when the URL reaches the end of the buffer — a
   confirmation timer (500ms) waits for more data before emitting

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app/src/lib/urlDetector.ts

@@ -4,6 +4,10 @@
  * The Linux PTY hard-wraps long lines with \r\n at the terminal column width,
  * which breaks xterm.js WebLinksAddon URL detection. This class reassembles
  * those wrapped URLs and fires a callback for ones >= 100 chars.
+ *
+ * Two-phase approach: when a URL candidate extends to the end of the buffer,
+ * emission is deferred (the rest of the URL may arrive in the next PTY chunk).
+ * A confirmation timer emits the pending URL if no further data arrives.
  */
 
 const ANSI_RE =
@@ -11,6 +15,7 @@ const ANSI_RE =
 
 const MAX_BUFFER = 8 * 1024; // 8 KB rolling buffer cap
 const DEBOUNCE_MS = 300;
+const CONFIRM_MS = 500; // extra wait when URL reaches end of buffer
 const MIN_URL_LENGTH = 100;
 
 export type UrlCallback = (url: string) => void;
@@ -19,7 +24,9 @@ export class UrlDetector {
   private decoder = new TextDecoder();
   private buffer = "";
   private timer: ReturnType<typeof setTimeout> | null = null;
+  private confirmTimer: ReturnType<typeof setTimeout> | null = null;
   private lastEmitted = "";
+  private pendingUrl: string | null = null;
   private callback: UrlCallback;
 
   constructor(callback: UrlCallback) {
@@ -35,8 +42,14 @@ export class UrlDetector {
       this.buffer = this.buffer.slice(-MAX_BUFFER);
     }
 
-    // Debounce — scan after 300 ms of silence
+    // Cancel pending timers — new data arrived, rescan from scratch
     if (this.timer !== null) clearTimeout(this.timer);
+    if (this.confirmTimer !== null) {
+      clearTimeout(this.confirmTimer);
+      this.confirmTimer = null;
+    }
+
+    // Debounce — scan after 300 ms of silence
     this.timer = setTimeout(() => {
       this.timer = null;
       this.scan();
@@ -47,26 +60,64 @@ export class UrlDetector {
     const clean = this.buffer.replace(ANSI_RE, "");
     const lines = clean.replace(/\r\n/g, "\n").replace(/\r/g, "\n").split("\n");
 
+    // Remove trailing empty elements (artifacts of trailing \n from split)
+    while (lines.length > 0 && lines[lines.length - 1] === "") {
+      lines.pop();
+    }
+
+    if (lines.length === 0) return;
+
     for (let i = 0; i < lines.length; i++) {
       const match = lines[i].match(/https?:\/\/[^\s'"]+/);
       if (!match) continue;
 
       // Start with the URL fragment found on this line
       let url = match[0];
+      let lastLineIndex = i;
 
       // Concatenate subsequent continuation lines (non-empty, no spaces, no leading whitespace)
       for (let j = i + 1; j < lines.length; j++) {
         const next = lines[j];
         if (!next || next.startsWith(" ") || next.includes(" ")) break;
         url += next;
+        lastLineIndex = j;
         i = j; // skip this line in the outer loop
       }
 
-      if (url.length >= MIN_URL_LENGTH && url !== this.lastEmitted) {
+      if (url.length < MIN_URL_LENGTH) continue;
+
+      // If the URL reaches the last line of the buffer, the rest may still
+      // be arriving in the next PTY chunk — defer emission.
+      if (lastLineIndex >= lines.length - 1) {
+        this.pendingUrl = url;
+        this.confirmTimer = setTimeout(() => {
+          this.confirmTimer = null;
+          this.emitPending();
+        }, CONFIRM_MS);
+        return;
+      }
+
+      // URL is clearly complete (more content follows it in the buffer)
+      this.pendingUrl = null;
+      if (url !== this.lastEmitted) {
         this.lastEmitted = url;
         this.callback(url);
       }
     }
+
+    // Scan finished without finding a URL reaching the buffer end.
+    // If we had a pending URL from a previous scan, it's now confirmed complete.
+    if (this.pendingUrl) {
+      this.emitPending();
+    }
+  }
+
+  private emitPending(): void {
+    if (this.pendingUrl && this.pendingUrl !== this.lastEmitted) {
+      this.lastEmitted = this.pendingUrl;
+      this.callback(this.pendingUrl);
+    }
+    this.pendingUrl = null;
   }
 
   dispose(): void {
@@ -74,5 +125,9 @@ export class UrlDetector {
       clearTimeout(this.timer);
       this.timer = null;
     }
+    if (this.confirmTimer !== null) {
+      clearTimeout(this.confirmTimer);
+      this.confirmTimer = null;
+    }
   }
 }