docs: add ansible howto collection

Four reference files covering:
- ansible.md — core commands, ansible.cfg, key settings
- ansible-inventory.md — static/dynamic inventory, directory layout
- ansible-variables.md — 22-level precedence, scoping, merge behavior
- ansible-roles.md — structure, defaults vs vars, dependencies

TASKS.md

@@ -3,8 +3,8 @@
 ## Current
 
 - [x] Scaffold project structure
-- [ ] Create topic template
-- [ ] Write first topic
+- [x] Create topic template
+- [x] Write first topic (ansible — 4 files)
 
 ## Backlog