Make reply ids unguessable and keep them out of the socket URL

Reply ids, which double as the proxy's run id, are now the same base36 ms
timestamp followed by a dash and 128 random bits from crypto.getRandomValues,
so a run can't be found by guessing. Saved replies keep their fields and the
timestamp prefix. The id is sent inside begin, resume and stop instead of the
URL, and SECURITY.md now says ntfy pings carry only the timestamp half.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/streaming.js

@@ -53,7 +53,6 @@ export const buildBody=()=>{
    you're elsewhere, reconnect on drops, and get picked back up after a reload. A streaming message carries
    stream:{seq} (the last chunk it holds) until it's finished. */
 const live=new Map();
-const wsUrl=rid=>`${WS_URL}?rid=${encodeURIComponent(rid)}`;
 const threadKey=tid=>(el.threadRepoInput.value.trim().startsWith('gh://')?'rem_t_':'t_')+tid;
 const saveLive=()=>localStorage.setItem(LIVE_KEY,JSON.stringify([...live.values()].map(s=>[s.rid,s.tid,s.key])));
 const onScreen=s=>window.state.currentThreadId===s.tid&&window.state.messages.includes(s.msg);
@@ -102,8 +101,9 @@ function finish(s,note=''){
 
 // Stops the run server-side too; without an open socket a throwaway one carries the stop
 function sendStop(s){
-  if(s.ws?.readyState===1)return s.ws.send('{"type":"stop"}');
-  const w=new WebSocket(wsUrl(s.rid));w.onopen=()=>{w.send('{"type":"stop"}');w.close()}
+  const m=JSON.stringify({type:'stop',rid:s.rid});
+  if(s.ws?.readyState===1)return s.ws.send(m);
+  const w=new WebSocket(WS_URL);w.onopen=()=>{w.send(m);w.close()}
 }
 
 // For a deleted message or thread: stop without saving anything
@@ -130,8 +130,8 @@ function onMessage(s,m){
 
 function connect(s){
   if(s.done)return;clearTimeout(s.timer);
-  const ws=s.ws=new WebSocket(wsUrl(s.rid));
-  ws.onopen=()=>ws.send(s.req||JSON.stringify({type:'resume',after:s.msg.stream.seq}));
+  const ws=s.ws=new WebSocket(WS_URL);
+  ws.onopen=()=>ws.send(s.req||JSON.stringify({type:'resume',rid:s.rid,after:s.msg.stream.seq}));
   ws.onmessage=e=>{if(s.ws!==ws)return;let m;try{m=JSON.parse(e.data)}catch{return}onMessage(s,m)};
   ws.onclose=()=>{
     if(s.ws!==ws||s.done)return;s.ws=null;retry(s)
@@ -165,7 +165,7 @@ export function startReply(msg){
   const apiKey=provider==='openai'?USER.apiKeyOpenAI:provider==='google'?USER.apiKeyGoogle:provider==='claude'?USER.apiKeyClaude:USER.apiKeyOpenRouter;
   const s=track(msg,state.currentThreadId,threadKey(state.currentThreadId));
   if(!apiKey){msg.content[0].text=window.localDemoReply();return finish(s)}
-  s.req=JSON.stringify({type:'begin',provider,apiKey,body:buildBody()});
+  s.req=JSON.stringify({type:'begin',rid:s.rid,provider,apiKey,body:buildBody()});
   if(s.req.length>MAX_REQ-(1<<20))return finish(s,'\n\nThis request is over the server’s 100 MB limit.');
   connect(s);syncBtn()
 }

src/utils.js

@@ -8,7 +8,8 @@ export const positionPopover = (a, p) => {
   p.style.top = `${r.bottom + p.offsetHeight + 4 > window.innerHeight ? r.top - p.offsetHeight - 4 : r.bottom + 4}px`;
   p.style.left = `${Math.max(8, Math.min(r.right - p.offsetWidth, window.innerWidth - p.offsetWidth - 8))}px`;
 };
-export const sid = () => Date.now().toString(36) + Math.random().toString(36).slice(2, 6);
+// Reply ids double as the proxy's run id, so after the ms timestamp come 128 random bits
+export const sid = () => Date.now().toString(36) + '-' + [...crypto.getRandomValues(new Uint8Array(16))].map(b => b.toString(16).padStart(2, '0')).join('');
 export const fmtSize = b => {
   const u = ['B', 'KB', 'MB', 'GB', 'TB'];
   let i = 0, x = b;