ui: keep detail-page SSE swaps live after the first outerHTML replace

Pipeline fragment payload was a bare <div class=pipeline>, but the
sse-swap=pipeline-N wrapper lived only in the page shell. The first
outerHTML swap destroyed the wrapper, so every subsequent pipeline
event had nothing to target — forcing a manual refresh. RenderPipelineString
now emits the full <section id=pipeline-N sse-swap=... hx-swap=outerHTML>
wrapper, used from both the shell and the orchestrator publish path.

Also drop the red-bar styling from the empty DetailHold placeholder:
the wrapper's detail-hold class was painting an unconditional red band
between Pipeline and Actions whenever no hold was active.

internal/web/templates/host_detail.templ

@@ -34,15 +34,7 @@ templ HostDetail(d HostDetailData) {
 			@DetailSummary(d)
 
 			if d.Tile.Latest != nil {
-				<section
-					id={ fmt.Sprintf("pipeline-%d", d.Tile.Latest.ID) }
-					class="detail-section"
-					sse-swap={ fmt.Sprintf("pipeline-%d", d.Tile.Latest.ID) }
-					hx-swap="outerHTML"
-				>
-					<h2>Pipeline</h2>
-					@Pipeline(BuildPipeline(d.Tile.Latest, d.Stages))
-				</section>
+				@PipelineSection(d.Tile.Latest, BuildPipeline(d.Tile.Latest, d.Stages))
 			} else {
 				<section class="detail-section">
 					<h2>Pipeline</h2>
@@ -206,17 +198,24 @@ templ DetailSpecDiffs(d HostDetailData) {
 // target. Keyed on run ID for the same reason as DetailSpecDiffs.
 templ DetailHold(d HostDetailData) {
 	if d.Tile.Latest != nil {
-		<section
-			id={ fmt.Sprintf("detail-hold-%d", d.Tile.Latest.ID) }
-			class="detail-section detail-hold"
-			sse-swap={ fmt.Sprintf("detail-hold-%d", d.Tile.Latest.ID) }
-			hx-swap="outerHTML"
-		>
-			if d.Tile.Latest.State == model.StateFailedHolding && d.Tile.Latest.HoldIP != "" {
+		if d.Tile.Latest.State == model.StateFailedHolding && d.Tile.Latest.HoldIP != "" {
+			<section
+				id={ fmt.Sprintf("detail-hold-%d", d.Tile.Latest.ID) }
+				class="detail-section detail-hold"
+				sse-swap={ fmt.Sprintf("detail-hold-%d", d.Tile.Latest.ID) }
+				hx-swap="outerHTML"
+			>
 				<h2>Host is holding — SSH available</h2>
 				<code class="hold-ssh">{ sshInvocation(d.Tile.HoldKeyPath, d.Tile.Latest.HoldIP) }</code>
-			}
-		</section>
+			</section>
+		} else {
+			<section
+				id={ fmt.Sprintf("detail-hold-%d", d.Tile.Latest.ID) }
+				class="detail-hold-placeholder"
+				sse-swap={ fmt.Sprintf("detail-hold-%d", d.Tile.Latest.ID) }
+				hx-swap="outerHTML"
+			></section>
+		}
 	}
 }