* Move globals into respective class

File-scope globals were shared across every instance of the class. If more than one SimpleStream instance were ever loaded, they would silently share the same stream list and TCP I/O service, likely causing data corruption and race conditions.

* Use const auto & in BOOST_FOREACH stream loops

Copying a struct with a raw pointer wont manage the socket lifetime, and two copies of the same pointer could interact badly. It also needlessly copies two std::string members and a UDP endpoint on every audio packet, which is a hot path. The const auto & form avoids all copies entirely. The start() and stop() loops already used auto& correctly, so this change just introduces consistency

* Wrap all TCP calls with try/catch and add error logging

Dropped TCP connections throws boots::system::system_error, which would terminate the TR process. It  should now log errors and continue. For UDP, there was no logging for errors to know when packets are dropped

* Use resolver for hostname support and add error logging

from_string() only accepts literal IP addresses, entering a hostname would throw an error and crash TR with no explanation.

* Implement URL-based configuration

Adds support for a url field in the simplestream config.  Can now be defined as udp://hostname:port or tcp://hostname:port instead of
separate address, port, and useTCP fields.

Added deprecation warning log and updated documentation to reflect changes and deprecation intent

* Merge master into PR #1123 (SimpleStream improvements)

Resolves conflicts in plugins/simplestream/simplestream.cc between the PR's
class-encapsulation/resolver work and master's ASIO modernization (#1129).

PR intent preserved:
- streams/io_context/max_tcp_index moved from file-scope globals into
  Simple_Stream class members
- BOOST_FOREACH loops use const auto& to avoid copying stream_t
- TCP send wrapped in try/catch; UDP send_to errors logged
- Hostname resolution support via resolver (now using the modern
  resolve(host, service) overload instead of the deprecated
  resolver::query / resolver::iterator API, since master moved to io_context)
- url-based config (udp://host:port / tcp://host:port) with deprecation
  warning for address/port/useTCP

Master changes preserved:
- io_service -> io_context rename (#1129) applied to both my_io_context
  and the moved my_tcp_io_context
- json_length scope fix (#1107) already absorbed via the PR base

Docs auto-merged: docs/CONFIGURE.md keeps both master's outputRawAudio
additions and the PR's url field documentation.


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Co-authored-by: jameson-dev <178156579+jameson-dev@users.noreply.github.com>