fix: resolve @file: protocol in all INIT consumers for Windows compatibility (#841)

When gsd-tools init output exceeds 50KB, core.cjs writes to a temp file
and outputs @file:<path>. No workflow handled this prefix, causing agents
to hallucinate /tmp paths that fail on Windows (C:\tmp doesn't exist).

Add @file: resolution line after every INIT=$(node ...) call across all
32 workflow, agent, and reference files.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

get-shit-done/workflows/map-codebase.md

@@ -27,6 +27,7 @@ Load codebase mapping context:
 
 ```bash
 INIT=$(node "$HOME/.claude/get-shit-done/bin/gsd-tools.cjs" init map-codebase)
+if [[ "$INIT" == @file:* ]]; then INIT=$(cat "${INIT#@file:}"); fi
 ```
 
 Extract from init JSON: `mapper_model`, `commit_docs`, `codebase_dir`, `existing_maps`, `has_maps`, `codebase_dir_exists`.