feat(0132): cpp terminal_panel module + ansi_parser

Nuevo modulo reutilizable terminal_panel (fn_term) para ImGui:

Sub-fn ansi_parser_cpp_core (cpp/functions/core/):
- Parser ANSI/VT100 byte-a-byte sin heap allocs por evento
- SGR colores FG/BG 16-color + bold + reset
- Cursor moves CUU/CUD/CUF/CUB + CUP absoluto
- Erase ED(2)/EL(2), CR/LF/BS
- Statemachine 4 estados, thread-unsafe por diseno
- 21 tests unitarios (57 assertions), todos pasan

terminal_panel_cpp_viz (cpp/functions/viz/terminal_panel/):
- terminal_panel.cpp: render ImGui + process_output con list clipper
- terminal_panel_linux.cpp: forkpty + reader thread no-blocking
- terminal_panel_windows.cpp: ConPTY CreatePseudoConsole (SDK >= 17763)
- Scrollback circular configurable (default 5000 lineas)
- Toolbar: clear, copy, reset, scroll-lock + status indicator
- readonly mode: sin input box, send() es no-op
- uses_functions: ansi_parser_cpp_core, logger_cpp_core

Tests:
- test_ansi_parser.cpp: 21 test cases, 57 assertions (PASS)
- test_terminal_panel_smoke.cpp: 3 test cases (PASS: spawn echo hello,
  process exits cleanly, readonly ignores send)

CMake:
- cpp/tests/CMakeLists.txt: add test_ansi_parser + test_terminal_panel_smoke
- primitives_gallery (sub-repo): ver commit separado en apps/primitives_gallery

Pendiente (anti-scope v1):
- Windows ConPTY: stub funcional que compila; join() del reader thread
  via std::thread no implementado (usa CreateThread detached)
- ANSI 256/24-bit color, italics, Unicode wide
- Curses pesados (vim, htop, top) — cursor visible basic solo

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cpp/tests/CMakeLists.txt

@@ -316,3 +316,20 @@ add_fn_test(test_agent_runs_timeline test_agent_runs_timeline.cpp
 add_fn_test(test_sse_client test_sse_client.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/../functions/core/sse_client.cpp
     ${CMAKE_CURRENT_SOURCE_DIR}/../functions/core/http_request.cpp)
+
+# --- Issue 0132 — ansi_parser: logica pura, sin ImGui ---
+add_fn_test(test_ansi_parser test_ansi_parser.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/../functions/core/ansi_parser.cpp)
+
+# --- Issue 0132 — terminal_panel smoke: spawn real PTY (Linux only) ---
+# En Windows: todos los casos se skipean via SKIP(). En Linux necesita -lutil.
+# Linkamos fn_framework para obtener logger.cpp (fn_log) + imgui + implot.
+add_fn_test(test_terminal_panel_smoke test_terminal_panel_smoke.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/../functions/core/ansi_parser.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/../functions/viz/terminal_panel/terminal_panel.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/../functions/viz/terminal_panel/terminal_panel_linux.cpp
+    ${CMAKE_CURRENT_SOURCE_DIR}/../functions/viz/terminal_panel/terminal_panel_windows.cpp)
+target_link_libraries(test_terminal_panel_smoke PRIVATE fn_framework)
+if(NOT WIN32)
+    target_link_libraries(test_terminal_panel_smoke PRIVATE util)
+endif()