feat: Dual-OS Neovim MCP Integration

- Created linux-nvim and win-nvim MCP servers for deep Neovim Msgpack-RPC integration.
- Implemented tools: nvim_goto_line, nvim_get_active_buffer, nvim_get_cursor, nvim_get_visual_selection, nvim_set_diagnostics.
- Added gemini-integration.lua for active UI socket discovery.
- Updated build.cmd to cross-compile for both Windows (gnu) and Linux (musl).
- Updated README, design.md, and instructions.md with architecture and tool capabilities.

instructions.md

@@ -131,3 +131,10 @@ When starting a new session, get a numerical aggregate of the project's current
 To maintain absolute traceability, we link memory items directly to the exact git commits they occurred on.
 - When calling **log_code_change**, **log_error_fix**, or **log_tech_debt**, you should execute git rev-parse HEAD and git branch --show-current in the project directory first (if it's a git repo).
 - Pass the resulting hash and branch name into the git_commit and git_branch arguments of those tools to permanently link the memory item to the VCS state.
+
+## 13. Server Lifecycle & Updates (Graceful Shutdown)
+When instructed to restart, update, or stop the mcp-memory-server binary, never use brute-force OS kill commands (e.g. Stop-Process, pkill, kill).
+- Why: The server uses asynchronous checkpointing. Force-killing it bypasses the shutdown flush, risking data loss in the master JSON graph, and can lead to lingering file locks.
+- How: Always use the built-in graceful shutdown mechanisms:
+  1. CLI Flag: mcp-memory-server --exit (or --restart)
+  2. HTTP Endpoint: POST http://127.0.0.1:3000/shutdown