fix(nestsClient): token-parse hardening, mint timeout, IPv6 [], broadcaster-bail signal

- NestsTokenResponse.parse catch list now includes IllegalStateException
  so a malformed escape from a misbehaving auth server surfaces as
  NestsException instead of crashing the listener.
- OkHttpNestsClient gains a configurable callTimeoutMs (default 90 s)
  enforcing an upper bound on the entire mintToken round-trip including
  retries. Without it a stalled server suspends the reconnect
  orchestrator indefinitely (the orchestrator's openOnce step parks on
  mintToken). 90 s leaves headroom over the worst-case 63 s 429
  retry chain documented in MAX_RATE_LIMIT_RETRIES.
- parseEndpoint tightens IPv6 bracket check from `closeBracket > 0` to
  `> 1`, rejecting the empty `[]` literal.
- NestBroadcaster + NestMoqLiteBroadcaster gain an `onTerminalFailure`
  callback that fires once when the consecutive-send-error guard bails.
  MoqLiteNestsSpeaker wires this to flip the speaker state to Failed,
  giving ReconnectingNestsSpeaker the signal it needs to recycle the
  session — without this hook the broadcaster bailed silently and the
  outward speaker state stayed on Broadcasting forever.

Adds regression test:
  - onTerminalFailure_fires_once_after_consecutive_send_failures

225 tests pass, 0 failures. Android target compiles clean.

nestsClient/src/commonMain/kotlin/com/vitorpamplona/nestsclient/NestsConnect.kt

@@ -372,7 +372,10 @@ internal fun parseEndpoint(endpoint: String): Pair<String, String> {
     val (hostPart, portStr) =
         if (authorityRaw.startsWith('[')) {
             val closeBracket = authorityRaw.indexOf(']')
-            require(closeBracket > 0) { "malformed IPv6 authority: '$authorityRaw'" }
+            // closeBracket==1 would mean the literal "[]" — empty IPv6
+            // address. Reject so callers can't accidentally pass an
+            // unconfigured placeholder.
+            require(closeBracket > 1) { "malformed IPv6 authority: '$authorityRaw'" }
             val host = authorityRaw.substring(0, closeBracket + 1)
             val tail = authorityRaw.substring(closeBracket + 1)
             when {