fix: set prebuilds lifecycle parameters on creation and claim (#19252)

## Description

This PR ensures that prebuilt workspaces are properly excluded from the
lifecycle executor and treated as a separate class of workspaces, fully
managed by the prebuild reconciliation loop.

It introduces two lifecycle guarantees:
* When a prebuilt workspace is created (i.e., when the workspace build
completes), all lifecycle-related fields are unset, ensuring the
workspace does not participate in TTL, autostop, autostart, dormancy, or
auto-deletion logic.
* When a prebuilt workspace is claimed, it transitions into a regular
user workspace. At this point, all lifecycle fields are correctly
populated according to template-level configurations, allowing the
workspace to be managed by the lifecycle executor as expected.

## Changes

* Prebuilt workspaces now have all lifecycle-relevant fields unset
during creation
* When a prebuild is claimed:
* Lifecycle fields are set based on template and workspace level
configurations. This ensures a clean transition into the standard
workspace lifecycle flow.
* Updated lifecycle-related SQL update queries to explicitly exclude
prebuilt workspaces.

## Relates 

Related issue: https://github.com/coder/coder/issues/18898

To reduce the scope of this PR and make the review process more
manageable, the original implementation has been split into the
following focused PRs:
* https://github.com/coder/coder/pull/19259
* https://github.com/coder/coder/pull/19263
* https://github.com/coder/coder/pull/19264
* https://github.com/coder/coder/pull/19265

These PRs should be considered in conjunction with this one to
understand the complete set of lifecycle separation changes for prebuilt
workspaces.

coderd/database/dbgen/dbgen.go

@@ -1436,11 +1436,25 @@ func UserSecret(t testing.TB, db database.Store, seed database.UserSecret) datab
 	return userSecret
 }
 
-func ClaimPrebuild(t testing.TB, db database.Store, newUserID uuid.UUID, newName string, presetID uuid.UUID) database.ClaimPrebuiltWorkspaceRow {
+func ClaimPrebuild(
+	t testing.TB,
+	db database.Store,
+	now time.Time,
+	newUserID uuid.UUID,
+	newName string,
+	presetID uuid.UUID,
+	autostartSchedule sql.NullString,
+	nextStartAt sql.NullTime,
+	ttl sql.NullInt64,
+) database.ClaimPrebuiltWorkspaceRow {
 	claimedWorkspace, err := db.ClaimPrebuiltWorkspace(genCtx, database.ClaimPrebuiltWorkspaceParams{
-		NewUserID: newUserID,
-		NewName:   newName,
-		PresetID:  presetID,
+		NewUserID:         newUserID,
+		NewName:           newName,
+		Now:               now,
+		PresetID:          presetID,
+		AutostartSchedule: autostartSchedule,
+		NextStartAt:       nextStartAt,
+		WorkspaceTtl:      ttl,
 	})
 	require.NoError(t, err, "claim prebuilt workspace")