nostr: make /rvrelay a true pin -- never merge discovered relays

A pool started with /rvrelay=ONE still spawned an accept thread for every
Nostr-discovered relay (BtfAllRelays always merged g_discoveredRelays), and
each thread optimistically overwrote the advertised meeting node before
registering -- so a discovered Tailscale-only relay (a mesh host)
flapped the published .btf descriptor and public miners could not connect.

fBtfRelayPinned (set only when /rvrelay parses) makes BtfAllRelays return
exactly the pinned list. Also validate the /rvrelay value at parse time:
with the pin in place no discovered relay can mask a typo.

(cherry picked from commit 0a4d2b02fa5382c5e788b5f0e2f8a844695dec47)

1 files changed, 8 insertions, 0 deletions

diff --git a/src/nostr.h b/src/nostr.h
index b5eb5e3..827b2f3 100644
--- a/src/nostr.h
+++ b/src/nostr.h
@@ -43,6 +43,14 @@ void BtfSetActiveRelay(const std::string& relay);
 // If set (via /announcerelay=host:port), this node announces that relay on
 // Nostr so other nodes discover it automatically -- no manual seed-list edit.
 extern std::string strBtfAnnounceRelay;
+// True when /rvrelay pinned the meeting relay list: BtfAllRelays then returns
+// ONLY vBtfMeetingRelays, never Nostr-discovered volunteer relays. Without
+// this, a pool that pins one public relay still spawns an accept thread per
+// discovered relay, and each thread's optimistic BtfSetActiveRelay makes the
+// published descriptor flap to relays the pool may not be reachable at.
+extern bool fBtfRelayPinned;
+// Basic sanity check on a "host:port" relay address (numeric port 1..65535).
+bool LooksLikeRelay(const std::string& r);
 // Every relay to try: curated seeds + relays discovered from Nostr announcements.
 std::vector<std::string> BtfAllRelays();