Implement bounded repository navigation with repo-lens

- Add map, find, and around commands with repository root discovery
- Stream literal ripgrep searches with match counts and result limits
- Add direct subprocess execution and explicit error returns
- Disable C++ exceptions and add navigation tests
- Support CMake installation and document builds and deployment
- Add a reusable agent skill and document skill discovery

src/repo_tool_map.cpp

@@ -1,10 +1,26 @@
+#include "navigation.hpp"
 #include "repo_tool_map.hpp"
 
+#include <iostream>
+
 namespace rl
 {
-    auto RepoLensToolMap::execute([[maybe_unused]] std::string_view args) noexcept -> exit_code
-    {
-        //@AGENT_TODO: Map tool implementation goes here
-        return 0;
-    }
+auto RepoLensToolMap::execute(arguments args) noexcept -> exit_code
+{
+	if (args.size() != 1 || args[0].empty())
+	{
+		std::cerr << "map: Usage: repo map <term> (non-empty term)" << '\n';
+		return 2;
+	}
+	std::filesystem::path root;
+	std::string error;
+	std::vector<std::string> lines;
+	if (!repository_root(root, error) || !read_lines(root / "docs" / "PROJECTMAP.md", lines, error))
+	{
+		std::cerr << "map: " << error << '\n';
+		return 2;
+	}
+	std::cout << map_sections(lines, args[0]);
+	return 0;
 }
+} // namespace rl