feat(pairing): seamless no-PIN delegated approval (host parks the knock, clients add "Request access")

Web-console "Approve" (delegated pairing, roadmap §8b-1) was unreachable: every
client routed a fresh pair=required host straight to the SPAKE2 PIN ceremony, so
no "knock" was ever recorded; and an unpaired connect was rejected+closed with no
way to resume after approval. The backend + console were complete but had no
client-side trigger and no post-approval admit path.

Host (native_pairing.rs, punktfunk1.rs): an unpaired identified knock is now
PARKED instead of rejected — it releases its NVENC session permit, awaits an
operator decision (NativePairing::wait_for_decision, woken by a Notify on
approve/deny), and on approval re-acquires a slot and admits the SAME connection
with no reconnect. QUIC keep-alive (4s/8s) holds the parked connection warm. The
pairing gate moves out of the HANDSHAKE_TIMEOUT-bounded handshake future;
approve_pending is reordered read-then-add and wait_for_decision double-checks
is_paired to close a "neither pending nor paired" race. New PENDING_APPROVAL_WAIT
(180s). Tests: delegated_approval_admits_after_knock now approves mid-park (no
reconnect) + new wait_for_decision_approve_deny_timeout unit test (108 host tests
green).

Clients (Linux/Apple/Windows/Android): a fresh pair=required host now offers
"Request access" alongside the PIN ceremony — a plain identified connect with a
~185s handshake budget and a cancelable "waiting for approval" UI; on success the
host is saved as paired, and cancel returns the UI immediately while a late-
resolving connect is torn down silently via a per-attempt flag. Apple reuses the
existing C-ABI timeout_ms (no ABI change); Windows adds SessionParams.connect_timeout
+ a RequestAccess screen; Android adds a timeoutMs arg to the nativeConnect JNI
seam (both sides + both callers). Linux built + clippy + fmt clean; Apple/Windows/
Android pending their CI/on-device compiles.

SPAKE2 ceremony reviewed end-to-end against the spake2 0.4 contract — correct, no
changes needed.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

clients/linux/src/session.rs

@@ -27,6 +27,11 @@ pub struct SessionParams {
     /// Pinned host fingerprint; `None` = trust on first use (caller persists the observed one).
     pub pin: Option<[u8; 32]>,
     pub identity: (String, String),
+    /// How long to wait for the handshake. The normal path uses a short budget; the
+    /// "request access" (delegated-approval) path uses a long one, because the host PARKS the
+    /// connection until the operator clicks Approve in its console (so this must exceed the
+    /// host's approval window — see `PENDING_APPROVAL_WAIT`).
+    pub connect_timeout: Duration,
 }
 
 #[derive(Clone, Copy, Default)]
@@ -139,7 +144,7 @@ fn pump(
         None, // launch: the Linux client has no library picker yet
         params.pin,
         Some(params.identity),
-        Duration::from_secs(15),
+        params.connect_timeout,
     ) {
         Ok(c) => Arc::new(c),
         Err(e) => {