v1.10.3

## Highlights
- Fix MCP process resolution on Windows and headless Linux so agent subprocesses never need PATH inheritance
- Bake a safe absolute binary fallback into the installed OpenCode plugin for headless and systemd environments
- Update Cursor docs to reflect the current `.cursor/rules/` MDC format and deprecate legacy `.cursorrules`

## Setup Improvements
- `engram setup claude-code` now writes a durable user-level MCP config at `~/.claude/mcp/engram.json` with the absolute binary path
- `engram setup opencode` now writes the resolved binary path in the MCP config and bakes a 3-tier fallback (`ENGRAM_BIN` env, `Bun.which`, absolute path) into the installed plugin
- `engram setup gemini-cli` and `engram setup codex` now use the absolute binary path on all platforms, not just Windows

## Docs
- Cursor section updated to recommend `.cursor/rules/engram.mdc` with `alwaysApply: true` frontmatter
- Added deprecation note for `.cursorrules` and version caveat for Cursor 0.43+

## Included Work
- fix(setup): use absolute MCP paths on Windows
- fix(setup): resolve OpenCode MCP path in generated config
- fix(setup): bake OpenCode plugin binary fallback
- docs(cursor): clarify mdc rules path, frontmatter, and deprecation notice