Add yaw2 invite interoperability

Protocol:
- invite.go: include full 64-char `net` hash in waste: invite blob
  (matches yaw2's `net` field — any client parsing the base64 JSON can
  join without knowing the plaintext name). Expose NetHash() helper.
- netmgr: add JoinByHash() — join via full 64-char hex hash alone,
  storing the short ID as display name. Enables joining yaw2 networks
  from a URL that only carries the hash.
- anchor: expose RunByHash() so netmgr can pass a pre-computed hash
  directly without a name→hash roundtrip.
- ipc/proto: add network_hash field to join_network — routes to
  JoinByHash when present and network_name is absent.

Web UI:
- Parse ?net=<64hex> (yaw2 URL param) and ?a=<anchor> in addition to
  existing ?n= / ?invite= params. Hash-only joins send network_hash.
- Sidebar shows yaw: contact card (yaw:<masterID>?n=<alias>) using the
  master identity — compatible with yaw2 contact card format. Click to
  copy to clipboard.

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

web/src/components/Sidebar.tsx

@@ -1,7 +1,12 @@
 import { useWaste } from '../store'
 
+function makeYawCard(id: string, alias: string): string {
+  const nick = encodeURIComponent(alias.trim().slice(0, 40))
+  return nick ? `yaw:${id}?n=${nick}` : `yaw:${id}`
+}
+
 export function Sidebar() {
-  const { localPeer, networks, activeNetworkId, activeRoom, setActiveRoom, setActiveNetwork, messages } = useWaste()
+  const { localPeer, masterId, masterAlias, networks, activeNetworkId, activeRoom, setActiveRoom, setActiveNetwork, messages } = useWaste()
 
   // Rooms = general + any DM threads that have messages
   const rooms = ['general']
@@ -9,11 +14,21 @@ export function Sidebar() {
     if (r.startsWith('dm:') && !rooms.includes(r)) rooms.push(r)
   })
 
+  const displayAlias = localPeer?.alias ?? masterAlias ?? ''
+  const displayId = localPeer?.id ?? masterId ?? ''
+  const card = displayId ? makeYawCard(displayId, displayAlias) : null
+
   return (
     <nav className="sidebar">
-      <div className="sidebar-identity">
-        <span className="alias">{localPeer?.alias}</span>
-        <span className="peer-id">{localPeer?.id.slice(0, 8)}…</span>
+      <div
+        className="sidebar-identity"
+        title={card ?? undefined}
+        onClick={() => card && navigator.clipboard?.writeText(card)}
+        style={{ cursor: card ? 'pointer' : undefined }}
+      >
+        <span className="alias">{displayAlias || '…'}</span>
+        <span className="peer-id">{displayId.slice(0, 16).replace(/(.{4})/g, '$1 ').trim()}</span>
+        {card && <span className="peer-id" style={{ fontSize: '9px', opacity: 0.5 }}>click to copy card</span>}
       </div>
 
       <div className="sidebar-section">