docs(#411): normalize AGENTS standards paths

AGENTS.md

@@ -3,7 +3,7 @@
 ## Load Order
 
 1. `SOUL.md` (repo identity + behavior invariants)
-2. `~/.mosaic/STANDARDS.md` (machine-wide standards rails)
+2. `~/.config/mosaic/STANDARDS.md` (machine-wide standards rails)
 3. `AGENTS.md` (repo-specific overlay)
 4. `.mosaic/repo-hooks.sh` (repo lifecycle hooks)
 
@@ -11,7 +11,7 @@
 
 - This file is authoritative for repo-local operations.
 - `CLAUDE.md` is a compatibility pointer to `AGENTS.md`.
-- Follow universal rails from `~/.mosaic/guides/` and `~/.mosaic/rails/`.
+- Follow universal rails from `~/.config/mosaic/guides/` and `~/.config/mosaic/rails/`.
 
 ## Session Lifecycle