Part of #31998.

coder templates create --dormancy-auto-deletion sets how long a workspace can stay dormant before it is deleted ("Dormancy Auto-Deletion" in the UI). coder templates push has no equivalent flag.

What to change

• New template: set CreateTemplateRequest.TimeTilDormantAutoDeleteMillis.
• Existing template: send UpdateTemplateMeta.TimeTilDormantAutoDeleteMillis only when the user sets the flag.
• License check required. This setting needs the Advanced Template Scheduling entitlement. On unlicensed (AGPL) deployments, the server keeps the old value without returning an error, so push would look like it worked when it didn't. Check entitlements first, the same way `create` and `edit` do. --failure-ttl, --dormancy-threshold and --dormancy-auto-deletion should share one check.

Scope: Small (S), about 20 lines plus a test. Add another 20 to 30 lines for whichever of the three adds the shared license check first.

Created on behalf of @angrycub