dsh-tool-reading-map: DeepSeek Harness Prioritized Codebase Reading Tool

`dsh-tool-reading-map` is a pluggable codebase mapping tool for DeepSeek Harness (DSH). It uses deterministic scanning to generate structured codebase maps for agents by priority (configuration, entry points, and source code), supporting custom file counts, preview line limits, and size constraints. The tool efficiently skips dependencies, binaries, and oversized files, provides honest coverage statistics, and helps agents quickly grasp the core context before editing.