fix(docs): commit package-lock.json to unblock GH Pages deploy

Root .gitignore excluded all package-lock.json files; add negation rule
for docs/package-lock.json so actions/setup-node cache-dependency-path
resolves correctly and the deploy workflow succeeds.

Author: jonathanperis

.gitignore

@@ -25,4 +25,5 @@ target/
 # Docs generation
 wiki/
 node_modules/
-package-lock.json
+package-lock.json
+!docs/package-lock.json