Wave 5+6: plugin ABI hardening, build modernization, ABI/security docs

Wave 5 (9 parallel agents):
- W1.1 atomic diag callback + DLL handle release on shutdown (lin)
- W2.1 unify cross-DLL heap discipline (host->alloc/free/strdup) (chen)
- W2.2 secure_zero api_key on shutdown for deepseek/anthropic (cao)
- W3 CMake modernization: target-based cxx_std_20, dstalk_boost_config
  INTERFACE lib, root-level RUNTIME_OUTPUT_DIRECTORY (hu)
- W4 GitHub Actions CI with dynamic Linux/Windows matrix (ma)
- W5.1 SSE buffer_body to cut peak memory ~67% on 32K streams (zhou)
- W6.1 LSP JSON-RPC frame parser hardened against header reordering (sun)
- W7 smoke test: copy plugin DLLs post-build + Boost.JSON src.hpp fix
  for full 9-plugin load coverage (wang)
- W8.1 README slimmed 398->92, Diataxis docs/ skeleton (deng)

Wave 6 (6 parallel agents):
- W9.1 docs/explanation: architecture + plugin-lifecycle (deng)
- W9.3 log credential leak audit (0 vulns, audit trail in
  docs/explanation/security-logging.md) (cao)
- W9.4 docs/reference/plugin-abi.md - 7-point ABI contract (lin)
- W9.6 CLI /history command + status integration (zhao)
- W9.8 plugin_loader fault tolerance: per-plugin failure no longer
  aborts dstalk_init (huang)
- W9.10 host_api unit tests: tests/host_api_test.cpp, 8 cases (liu)

CEO oversight (preexisting bugs fixed during Wave 5 verification):
- lsp_plugin.cpp:449 forward decl mismatch (int vs void)
- tools_plugin.cpp:109 missing forward decl

Multi-agent collaboration framework:
- agents/WORKFLOW.md: 6-stage protocol, two-tier governance,
  prompt template, technical constraints registry

Build: cmake --build 0 error / 0 warning. Tests: 2/2 100% pass.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

tests/CMakeLists.txt

@@ -10,10 +10,27 @@ target_link_libraries(dstalk-smoke-test
     PRIVATE dstalk
 )
 
-add_custom_command(TARGET dstalk-smoke-test POST_BUILD
-    COMMAND ${CMAKE_COMMAND} -E copy_if_different
-        $<TARGET_FILE:dstalk>
-        $<TARGET_FILE_DIR:dstalk-smoke-test>
+add_test(NAME dstalk-smoke-test COMMAND dstalk-smoke-test)
+
+# ============================================================
+# dstalk-host-api-test — host API 单元测试
+# ============================================================
+
+add_executable(dstalk-host-api-test
+    host_api_test.cpp
+    ${CMAKE_SOURCE_DIR}/dstalk-core/src/service_registry.cpp
 )
 
-add_test(NAME dstalk-smoke-test COMMAND dstalk-smoke-test)
+target_include_directories(dstalk-host-api-test
+    PRIVATE ${CMAKE_SOURCE_DIR}/dstalk-core/src
+)
+
+target_compile_features(dstalk-host-api-test
+    PRIVATE cxx_std_17
+)
+
+target_link_libraries(dstalk-host-api-test
+    PRIVATE dstalk
+)
+
+add_test(NAME dstalk-host-api-test COMMAND dstalk-host-api-test)