## Description
This PR ensures that lifecycle-related changes made via template
schedule updates do **not affect prebuilt workspaces**. Since prebuilds
are managed by the reconciliation loop and do not participate in the
regular lifecycle executor flow, they must be excluded from any updates
triggered by template configuration changes.
This includes changes to TTL, dormant-deletion scheduling, deadline and
autostart scheduling.
## Changes
- Updated SQL query `UpdateWorkspacesTTLByTemplateID` to exclude
prebuilt workspaces
- Updated SQL query `UpdateWorkspacesDormantDeletingAtByTemplateID` to
exclude prebuilt workspaces
- Updated application-layer logic to skip any updates to lifecycle
parameters if a workspace is a prebuild
- Preserved all existing update behavior for regular user workspaces
This change guarantees that only lifecycle-managed workspaces are
affected when template-level configurations are modified, preserving
strict boundaries between prebuild and user workspace lifecycles.
Related with:
* Issue: https://github.com/coder/coder/issues/18898
* PR: https://github.com/coder/coder/pull/19252
Susana Ferreira
d79a7797c2