docs: establish the constellation Git baseline

Condense the working handoff into implemented state, activation evidence and open choices. Record both repositories, flag superseded SharePoint setup instructions and undocumented input/support changes, and align the design with completed workbench organization.

Keep the generated nvim.log locally but ignore it. Both flakes evaluated successfully and whitespace checks passed. No implementation behavior changes, tests, builds, activation or remote writes.

.gitignore

@@ -4,3 +4,4 @@
 .opencode
 
 result
+/nvim.log