Add peer-to-peer file transfer in browser mode

Implements both pull (browse & download from a shared folder) and push
(send a file directly to a peer) using the yaw2 file protocol over WebRTC
DataChannels.

- PeerConn: handle browse/files/get/file-offer/file-accept/file-done
  control messages; stream files in 64KB chunks over f:xid binary
  DataChannels; auto-accept incoming offers (push and pull)
- PeerConn.sendFilePush(): initiate an outbound file transfer without
  requiring the peer to browse first
- BrowserAdapter: sharedFiles map, setSharedFiles(), requestBrowse(),
  requestGet(), sendFileTo() — propagates share map to all active peers
- Store: activeFilePeer, setActiveFilePeer, setSharedFiles, browseFiles,
  sendFileTo; file_complete handler triggers browser download automatically
- FileBrowser component: third-column panel listing a peer's shared files
  with name, size, and a download button
- FolderPicker component: webkitdirectory input in the sidebar (browser
  mode only) for selecting a local folder to share
- Sidebar: 📎 send-file button on peer rows (hover) with inline file picker
- App.tsx: use browser mode when WASTE_CONFIG.signalURL is set, even on
  localhost — allows testing browser mode via npm run dev with config.js
- deploy-daemon.sh: kill existing daemon before scp to avoid upload failure
  when the binary is locked; remove duplicate kill block in restart step

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

web/src/components/FileBrowser.tsx

@@ -0,0 +1,48 @@
+import { useWaste } from '../store'
+import { BrowserAdapter } from '../adapter/browser'
+
+function fmt(bytes: number): string {
+  if (bytes < 1024) return `${bytes} B`
+  if (bytes < 1024 * 1024) return `${(bytes / 1024).toFixed(1)} KB`
+  return `${(bytes / (1024 * 1024)).toFixed(1)} MB`
+}
+
+export function FileBrowser() {
+  const { activeFilePeer, fileLists, setActiveFilePeer, adapter, connectedPeers } = useWaste()
+
+  if (!activeFilePeer) return null
+
+  const peer = connectedPeers.find(p => p.id === activeFilePeer)
+  const files = fileLists[activeFilePeer] ?? null
+
+  function download(name: string) {
+    if (adapter instanceof BrowserAdapter) {
+      adapter.requestGet(activeFilePeer!, name)
+    }
+  }
+
+  return (
+    <div className="file-browser">
+      <div className="file-browser-header">
+        <span className="file-browser-title">Files · {peer?.alias ?? activeFilePeer.slice(0, 8)}</span>
+        <button className="file-browser-close" onClick={() => setActiveFilePeer(null)}>✕</button>
+      </div>
+
+      {files === null ? (
+        <div className="file-browser-empty">Loading…</div>
+      ) : files.length === 0 ? (
+        <div className="file-browser-empty">No files shared</div>
+      ) : (
+        <ul className="file-list">
+          {files.map(f => (
+            <li key={f.name} className="file-entry">
+              <span className="file-entry-name">{f.name}</span>
+              <span className="file-entry-size">{fmt(f.size_bytes)}</span>
+              <button className="file-entry-dl" onClick={() => download(f.name)}>↓</button>
+            </li>
+          ))}
+        </ul>
+      )}
+    </div>
+  )
+}

web/src/components/FolderPicker.tsx

@@ -0,0 +1,43 @@
+import { useRef, useState } from 'react'
+import { useWaste } from '../store'
+
+export function FolderPicker() {
+  const { setSharedFiles } = useWaste()
+  const inputRef = useRef<HTMLInputElement>(null)
+  const [label, setLabel] = useState<string | null>(null)
+
+  function onChange(e: React.ChangeEvent<HTMLInputElement>) {
+    const fileList = e.target.files
+    if (!fileList || fileList.length === 0) return
+    const map = new Map<string, File>()
+    for (let i = 0; i < fileList.length; i++) {
+      const f = fileList[i]
+      map.set(f.name, f)
+    }
+    setSharedFiles(map)
+    const first = fileList[0]
+    const parts = (first.webkitRelativePath || first.name).split('/')
+    setLabel(`${parts[0]} (${map.size} file${map.size !== 1 ? 's' : ''})`)
+  }
+
+  return (
+    <div className="folder-picker">
+      <input
+        ref={inputRef}
+        type="file"
+        // @ts-expect-error webkitdirectory is non-standard
+        webkitdirectory=""
+        multiple
+        style={{ display: 'none' }}
+        onChange={onChange}
+      />
+      <button
+        className="folder-picker-btn"
+        onClick={() => inputRef.current?.click()}
+        title="Share a folder with peers"
+      >
+        {label ?? '+ Share folder'}
+      </button>
+    </div>
+  )
+}

web/src/components/Sidebar.tsx

@@ -1,5 +1,6 @@
 import { useWaste } from '../store'
 import type { PeerStatus } from '../store'
+import { FolderPicker } from './FolderPicker'
 
 function makeYawCard(id: string, alias: string): string {
   const nick = encodeURIComponent(alias.trim().slice(0, 40))
@@ -28,7 +29,7 @@ export function Sidebar() {
     localPeer, masterId, masterAlias,
     networks, activeNetworkId, activeRoom,
     connectedPeers, peerStatus,
-    setActiveRoom, setActiveNetwork, messages, send,
+    setActiveRoom, setActiveNetwork, messages, browseFiles, sendFileTo, adapterMode,
   } = useWaste()
 
   const rooms = ['general']
@@ -45,7 +46,7 @@ export function Sidebar() {
   }
 
   function requestFiles(peerId: string) {
-    send({ type: 'get_file_list', network_id: activeNetworkId ?? undefined, peer_id: peerId })
+    browseFiles(peerId)
   }
 
   return (
@@ -86,6 +87,13 @@ export function Sidebar() {
         ))}
       </div>
 
+      {adapterMode === 'browser' && (
+        <div className="sidebar-section">
+          <span className="sidebar-label">Sharing</span>
+          <div style={{ padding: '4px 12px' }}><FolderPicker /></div>
+        </div>
+      )}
+
       <div className="sidebar-section sidebar-peers">
         <span className="sidebar-label">Peers · {connectedPeers.length + 1}</span>
 
@@ -116,7 +124,15 @@ export function Sidebar() {
               <span className="peer-row-id">{p.id.slice(0, 8)}</span>
               <span className="peer-row-actions">
                 <button className="peer-action" onClick={() => openDM(p.id)} title="DM">↩</button>
-                <button className="peer-action" onClick={() => requestFiles(p.id)} title="Files">⊞</button>
+                <button className="peer-action" onClick={() => requestFiles(p.id)} title="Browse files">⊞</button>
+                <label className="peer-action" title="Send file" style={{ cursor: 'pointer' }}>
+                  📎
+                  <input type="file" style={{ display: 'none' }} onChange={e => {
+                    const f = e.target.files?.[0]
+                    if (f) sendFileTo(p.id, f)
+                    e.target.value = ''
+                  }} />
+                </label>
               </span>
             </div>
           )