chore: tidy before tag

Update .gitignore (add .local/, remove stale spec entry).
Remove TODO.md (moved to .local/done/).
Remove docs/ISSUE_TEMPLATE.md (moved to .local/).

.gitignore

@@ -22,9 +22,6 @@ nib
 .DS_Store
 Thumbs.db
 
-# Spec (not shipped)
-nib-unified-spec.md
-
 # Shell/profile dotfiles (host artifacts)
 .bash_profile
 .bashrc
@@ -35,3 +32,6 @@ nib-unified-spec.md
 .gitmodules
 .ripgreprc
 .mcp.json
+
+# Local Documents
+.local/