docs: TCPStreamer source kind spec and plan

docs/superpowers/specs/2026-11-06-tcp-streamer-source-design.md

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+# TCPStreamer source kind
+
+A new source kind `tcps` ("TCPStreamer") that receives a MARTe2 `TCPStreamer` DataSource, either
+standalone or through a shared `TCPStreamService`.
+
+## Wire and scope
+
+- Both transports are plain UDPS framing over TCP. A standalone `TCPStreamer` (TCPSServer) sends
+  CONFIG then DATA on connect. A `TCPStreamService` additionally requires a first client frame,
+  `SUBSCRIBE` (type 5, payload = stream name, 1..255 bytes).
+- A plain server ignores `SUBSCRIBE`, so the client sends it only when a stream name is set.
+- One connection carries one stream. Multiplexed lists (`"a,b,c"`, stream index in `fragmentIdx`)
+  are out of scope: a udpscope source is single-timebase. Several streams are merged server-side
+  with `TCPStreamJoin`, which publishes an ordinary named stream.
+
+## `deps/udpsclient`: a TCP transport mode
+
+- `udps_client_config_t` gains `use_tcp` and `stream_name`.
+- New `connect_tcp()`: open the TCP socket, send `SUBSCRIBE` if a stream name is set, send no
+  `CONNECT`. No UDP socket, no keepalive ACK.
+- `udps_client_poll` reuses `read_tcp_frame` / `handle_packet`.
+- `reorder_window_s` is forced to 0 in TCP mode: TCP is ordered, so a counter gap is a server-side
+  drop and is reported at once.
+- Silence timeout and reconnect delay behave as in UDP (dead server, or a stalled client the server
+  evicted, reconnects).
+- The datagram tap does not fire; the packet capture stays UDP-only (`has_datagrams()` false).
+- Additive. Recorded in `docs/claude/build-and-run.md` as a sixth intentional upstream change.
+
+## Source adapter and kind
+
+- `UdpsSource` takes a transport argument (`UdpsSource(cfg, Transport::Tcp)`) instead of being
+  copied: its callbacks are identical. The TCP variant reads `server`, `port` (default 44500) and
+  `stream`.
+- `src/source/tcps_kind.cpp`: kind `tcps`, display name "TCPStreamer". Form rows: Server, Port,
+  Stream name (optional). Description: "Leave empty for a standalone TCPStreamer; name the stream
+  for a TCPStreamService".
+- Identity: `host:port` or `host:port/stream`. Session naming follows the existing non-UDPS rule
+  (`tcps-<identity>`, port 1, `source_kind=tcps`, `source_opt_*`).
+- Registered in `register_builtin_sources()` and `CMakeLists.txt`.
+
+## Verification
+
+No unit suite. Extend the self-check in `src/ui_probe.cpp` with an in-process fake TCP server that
+sends CONFIG then DATA, and requires `SUBSCRIBE` in one mode. Probe lines assert the signals, the
+frame count, and the reconnect after the server closes. Baselines: exactly one build warning, no
+`Gtk-CRITICAL`. A smoke test against a real MARTe `TCPStreamer` if one is runnable.
+
+## Docs
+
+README and `docs/claude/architecture.md` (Sources) describe the kind; `docs/claude/probe-readings.md`
+gets the new probe lines.