fix(ci): harden Molecule download and cleanup

- Retry transient k3s release downloads with bounded backoff.\n- Bound failure diagnostics and validate guest release connectivity.\n- Discover repository-owned Molecule state under the actual project root.

roles/download/tasks/main.yml

@@ -7,6 +7,10 @@
     owner: root
     group: root
     mode: "0755"
+  register: k3s_download_x64
+  retries: 5
+  delay: 10
+  until: k3s_download_x64 is succeeded
   when: ansible_facts.architecture == "x86_64"
 
 - name: Download k3s binary arm64
@@ -17,6 +21,10 @@
     owner: root
     group: root
     mode: "0755"
+  register: k3s_download_arm64
+  retries: 5
+  delay: 10
+  until: k3s_download_arm64 is succeeded
   when:
     - ( ansible_facts.architecture is search("arm") and ansible_facts.userspace_bits == "64" )
       or ansible_facts.architecture is search("aarch64")
@@ -29,6 +37,10 @@
     owner: root
     group: root
     mode: "0755"
+  register: k3s_download_armhf
+  retries: 5
+  delay: 10
+  until: k3s_download_armhf is succeeded
   when:
     - ansible_facts.architecture is search("arm")
     - ansible_facts.userspace_bits == "32"