feat(mining): host a RandomX stratum pool from the node (v1.3.0+)

Add an opt-in "Host a mining pool (stratum)" toggle so a v1.3.0+ node can run its native
RandomX stratum server for other miners to point at. Settings toggle + optional allow-IP/CIDR;
passes -stratum (+ -stratumallowip) to the daemon launch args, mirroring the -maxconnections
plumbing (EmbeddedDaemon::setStratumHosting <- DaemonController::syncSettings <- Settings).

Backwards compatible / safe by default:
- UI gated on daemon_version >= 1030000, so it's never offered where it would do nothing.
- The launch flag is harmless on older daemons (they ignore unknown args), and the toggle can
  only be enabled while connected to a v1.3.0+ node anyway.
- Blank allow-IP => the daemon serves loopback only (its safe default); entering a subnet opens
  it to that LAN, with an explicit exposure warning in the UI.
- Takes effect on the next daemon start/restart.

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

src/util/i18n.cpp

@@ -730,6 +730,11 @@ void I18n::loadBuiltinEnglish()
         strings_["tt_tor"] = "Route daemon connections through the Tor network for anonymity";
         strings_["tt_keep_daemon"] = "Daemon will still stop when running the setup wizard";
         strings_["tt_stop_external"] = "Applies when connecting to a daemon\nyou started outside this wallet";
+        strings_["stratum_host"] = "Host a mining pool (stratum)";
+        strings_["tt_stratum_host"] = "Run a RandomX stratum pool server on this node so other RandomX miners can point at this computer. Requires a v1.3.0+ node and a daemon restart to apply.";
+        strings_["stratum_host_hint"] = "Miners connect to this computer on port 22769 (RPC port + 1000) with a RandomX stratum miner. Restart the daemon to apply.";
+        strings_["stratum_allowip_hint"] = "Allow miners from IP or CIDR (blank = this computer only)";
+        strings_["stratum_expose_warn"] = "Opens a mining port to the network you allow — only use on a trusted LAN.";
         strings_["tt_verbose"] = "Log detailed connection diagnostics,\ndaemon state, and port owner info\nto the Console tab";
         strings_["tt_mine_idle"] = "Automatically start mining when the\nsystem is idle (no keyboard/mouse input)";
         strings_["tt_idle_delay"] = "How long to wait before starting mining";