Stop tracking runtime data; seed from *.example.json

data/profiles.json and data/users.json hold live tenant config and
user records that the app rewrites at runtime (lastLogin etc.), so they
dirtied git status on every run. Untrack them and gitignore data/*.json
(plus logs/exports/templates/audit), keeping committed *.example.json
seeds. Repositories already create empty files on first save, so a
fresh clone starts clean and provisions the first user as Admin.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

data/users.example.json

@@ -0,0 +1,3 @@
+{
+  "users": []
+}