Caddy: adopt dual-role snippet (PB api+admin on main host), relative PB file urls

- www host: /_* and /api/* proxy to pocketbase :8090, everything else to
  the TanStack app; redir /_ /_/ for the admin path
- cms host unchanged: redir / -> /_/
- migration: legacy per-host marker blocks are removed before the new
  combined block is installed
- cms.ts: PB file urls are now same-origin relative (/api/files/...) —
  browsers could never load the old 127.0.0.1:8090 urls; validated the
  rendered Caddyfile with caddy:2

ansible/roles/caddy/tasks/main.yaml

@@ -1,15 +1,3 @@
 ---
-- name: Read current Caddyfile
-  ansible.builtin.slurp:
-    path: "{{ caddyfile_path }}"
-  register: caddyfile_raw
-
-- name: Decode Caddyfile content
-  set_fact:
-    caddyfile_content: "{{ caddyfile_raw['content'] | b64decode }}"
-
-- name: Add Caddy snippets for each published host
+- name: Install mozimo Caddy snippet (web + cms)
   ansible.builtin.include_tasks: snippet.yaml
-  loop: "{{ caddy_hosts }}"
-  loop_control:
-    loop_var: snippet