Refactor to plugin architecture with B3 CLI UX, C2 smoke tests, C3 CI scripts

Architecture overhaul (Wave 1-4 collaborative work):
- Migrated dstalk-core from monolithic api.cpp to plugin-based design with
  host/service_registry/event_bus/plugin_loader and topological initialization.
- Split public headers into dstalk_host.h / dstalk_services.h /
  dstalk_lsp.h / dstalk_types.h; deleted obsolete dstalk_api.h and inlined
  TLS/file/net code now provided by plugins.
- Added 9 plugins: deepseek, anthropic, network, session, context, tools,
  config, file-io, lsp; AI plugins register as "ai.<provider>" services.

B3 CLI interaction enhancement:
- Prompt now shows current model name (A1).
- /status command prints model/base_url/api_key (sanitized: shown only
  as set/unset)/services readiness (A2).
- SIGINT/Ctrl+C handled on POSIX (signal) and Windows (SetConsoleCtrlHandler);
  /quit no longer std::exit(0) but sets a quit flag so dstalk_shutdown runs
  exactly once via natural control flow (B1+B2).
- Cross-DLL free fixed: print_file uses dstalk_free instead of std::free (B4).
- --batch mode plus isatty auto-detection for piped stdin (C1).
- fgets truncation detection with friendly error and stdin draining (C3).
- Distinct exit codes (init/AI/service-unavailable) (C4).
- /model rejects empty model name (C5).

C2 smoke test extension:
- 4 new test blocks: null-safety (file_io/session/tools/config),
  escape-boundary round-trip, tools->execute call chain, session robustness
  (add(nullptr), clear -> token_count == 0).

C3 CI build scripts:
- scripts/ci-build.sh and scripts/ci-build.bat invoke cmake configure +
  parallel build + ctest, suitable for GitHub Actions.

Build verified: dstalk-cli compiles, smoke test passes via ctest.

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

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

dstalk-core/src/config_store.cpp

@@ -0,0 +1,83 @@
+#include "config_store.hpp"
+
+#include <cstdio>
+#include <fstream>
+#include <sstream>
+#include <string>
+
+namespace dstalk {
+
+int ConfigStore::load_file(const char* path)
+{
+    if (!path) return -1;
+
+    std::ifstream file(path);
+    if (!file.is_open()) return -1;
+
+    std::stringstream ss;
+    ss << file.rdbuf();
+    std::string data = ss.str();
+
+    // 简易 TOML 解析：只处理 [section] 和 key = "value"
+    std::string current_section;
+    size_t pos = 0;
+    while (pos < data.size()) {
+        while (pos < data.size() && (data[pos] == ' ' || data[pos] == '\t'))
+            pos++;
+        if (pos >= data.size()) break;
+
+        size_t nl = data.find('\n', pos);
+        std::string line = (nl != std::string::npos)
+            ? data.substr(pos, nl - pos) : data.substr(pos);
+        pos = (nl != std::string::npos) ? nl + 1 : data.size();
+
+        while (!line.empty() && (line.back() == '\r' || line.back() == ' '))
+            line.pop_back();
+
+        if (line.empty() || line[0] == '#') continue;
+
+        if (line[0] == '[' && line.back() == ']') {
+            current_section = line.substr(1, line.size() - 2);
+            continue;
+        }
+
+        size_t eq = line.find('=');
+        if (eq == std::string::npos) continue;
+
+        std::string key = line.substr(0, eq);
+        while (!key.empty() && key.back() == ' ') key.pop_back();
+        if (key.empty()) continue;
+
+        std::string val = line.substr(eq + 1);
+        while (!val.empty() && (val.front() == ' ' || val.front() == '\t'))
+            val.erase(0, 1);
+        if (val.size() >= 2 && val.front() == '"' && val.back() == '"')
+            val = val.substr(1, val.size() - 2);
+
+        std::lock_guard<std::mutex> lock(mutex_);
+        std::string full_key = current_section.empty()
+            ? key : current_section + "." + key;
+        data_[full_key] = val;
+    }
+
+    return 0;
+}
+
+const char* ConfigStore::get(const char* key) const
+{
+    if (!key) return nullptr;
+    std::lock_guard<std::mutex> lock(mutex_);
+    auto it = data_.find(key);
+    if (it == data_.end()) return nullptr;
+    return it->second.c_str();
+}
+
+int ConfigStore::set(const char* key, const char* value)
+{
+    if (!key || !value) return -1;
+    std::lock_guard<std::mutex> lock(mutex_);
+    data_[key] = value;
+    return 0;
+}
+
+} // namespace dstalk