container: plugins: root: add bitcoin plugin

Utilizes `libbitcoinkernel` for symbols and headers but also pulls from
non-kernel headers as needed (since current kernel design is a WIP).

See the code documentation in this commit for details.

container/plugins/root/bitcoin/bitcoin.cc

@@ -0,0 +1,104 @@
+// docker-finance | modern accounting for the power-user
+//
+// Copyright (C) 2025 Aaron Fiore (Founder, Evergreen Crypto LLC)
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation  either version 3 of the License  or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not  see <https://www.gnu.org/licenses/>.
+
+//! \file
+//! \author Aaron Fiore (Founder, Evergreen Crypto LLC)
+//! \note File intended to be loaded into ROOT.cern framework / Cling interpreter
+//! \since docker-finance 1.1.0
+
+//! \namespace dfi::plugin
+//! \brief docker-finance plugins
+//! \warning All plugins (repo/custom) must exist within this namespace
+//!   and work within their own inner namespace
+//! \since docker-finance 1.0.0
+namespace dfi::plugin
+{
+//! \namespace dfi::plugin::bitcoin
+//! \brief docker-finance bitcoin plugin namespace
+//! \warning Bitcoin inherently pollutes the global namespace - be wary
+//! \since docker-finance 1.1.0
+namespace bitcoin
+{
+//! \brief Get container-side path to bitcoin repository
+//! \return Absolute path of shared (bind-mounted) bitcoin repository
+//! \todo To avoid future include conflicts, consider adjusting base path
+//! \since docker-finance 1.1.0
+inline std::string get_repo_path()
+{
+  return ::dfi::common::get_env("DOCKER_FINANCE_CONTAINER_SHARED")
+         + "/bitcoin/";
+}
+
+//! \brief Initialize this bitcoin plugin
+//! \details Bare-essential initializations, will require manual loading for any further functionality
+//! \warning Initializations *MUST* occur here before any other bitcoin lib use
+//! \ingroup cpp_plugin_impl
+//! \since docker-finance 1.1.0
+void load(const std::string& arg = {})
+{
+  namespace common = ::dfi::common;
+
+  const std::string repo{get_repo_path()};
+
+  // Minimum requirements
+  common::add_include_dir(repo + "src");
+  common::add_linked_lib(repo + "build/lib/libbitcoinkernel.so");
+  // WARNING: assertions *MUST* be enabled before loading any bitcoin headers
+  common::line("#undef NDEBUG");
+  common::load(repo + "src/kernel/bitcoinkernel_wrapper.h");
+
+  // `dfi`-specific requirements (API, macros, tests, etc.)
+  common::line("#define __DFI_PLUGIN_BITCOIN__");
+  common::load(repo + "src/random.h");
+  // ...add as needed
+
+  if (!arg.empty())
+    common::line(arg);
+}
+
+//! \brief Deinitialize this bitcoin plugin
+//! \details Bare-essential deinitializations, will require manual unloading for any other previously loaded functionality
+//! \warning Unloading certain bitcoin headers may result in Cling segfault due to bitcoin library design
+//! \ingroup cpp_plugin_impl
+//! \since docker-finance 1.1.0
+//! \todo It appears that, due to bitcoin design, unloading will result in
+//!   Cling segfault "*** Break *** illegal instruction". With that said, it's
+//!   best to exit `root` if you want a clean workspace (instead of unloading this plugin).
+void unload(const std::string& arg = {})
+{
+  namespace common = ::dfi::common;
+
+  if (!arg.empty())
+    common::line(arg);
+
+  const std::string repo{get_repo_path()};
+
+  // `dfi`-specific requirements (API, macros, tests, etc.)
+  common::line("#undef __DFI_PLUGIN_BITCOIN__");
+  common::unload(repo + "src/random.h");
+  // ...add as needed
+
+  // Minimum requirements
+  common::unload(repo + "src/kernel/bitcoinkernel_wrapper.h");
+  common::line("#define NDEBUG");
+  // TODO(unassigned): remove_include_dir()
+  common::remove_linked_lib(repo + "build/lib/libbitcoinkernel.so");
+}
+}  // namespace bitcoin
+}  // namespace dfi::plugin
+
+// # vim: sw=2 sts=2 si ai et