`fix(performance-profiler): make non-fullscreen layout fill to footer

- update profiler-specific tool-shell sizing to match fullscreen behavior in normal mode
- set explicit available-height container sizing for non-fullscreen (`100dvh`-based)
- ensure `.tool-shell` participates in flex fill (`flex: 1 1 auto`, `height: 100%`)
- keep left/center/right columns stretched and output pane internally scrollable
- preserve existing fullscreen behavior while aligning normal-mode vertical fill`

Author: DavidQ

src/engine/theme/tool-shell.css

@@ -76,6 +76,59 @@
   overflow: auto;
 }
 
+body[data-tool-id="performance-profiler"].tool-shell-page .tool-shell-container {
+  flex: 1 1 auto;
+  height: calc(100dvh - 120px);
+  min-height: 0;
+  display: flex;
+  flex-direction: column;
+}
+
+body[data-tool-id="performance-profiler"].tool-shell-page {
+  min-height: 100dvh;
+  display: flex;
+  flex-direction: column;
+}
+
+body[data-tool-id="performance-profiler"].tool-shell-page > .is-collapsible,
+body[data-tool-id="performance-profiler"].tool-shell-page > [data-tools-platform-status] {
+  flex: 0 0 auto;
+}
+
+body[data-tool-id="performance-profiler"].tool-shell-page .tool-shell-container {
+  min-height: 420px;
+}
+
+body[data-tool-id="performance-profiler"].tool-shell-page .tool-shell {
+  min-height: 0;
+  max-height: none;
+  height: 100%;
+  flex: 1 1 auto;
+}
+
+body[data-tool-id="performance-profiler"].tool-shell-page .tool-shell__left,
+body[data-tool-id="performance-profiler"].tool-shell-page .tool-shell__center,
+body[data-tool-id="performance-profiler"].tool-shell-page .tool-shell__right {
+  min-height: 0;
+}
+
+body[data-tool-id="performance-profiler"].tool-shell-page .tool-shell__left > .debug-tool-panel,
+body[data-tool-id="performance-profiler"].tool-shell-page .tool-shell__center > .debug-tool-panel,
+body[data-tool-id="performance-profiler"].tool-shell-page .tool-shell__right > .debug-tool-panel {
+  min-height: 0;
+  height: 100%;
+  display: flex;
+  flex-direction: column;
+}
+
+body[data-tool-id="performance-profiler"].tool-shell-page #profileOutput {
+  min-height: 0;
+  height: 100%;
+  max-height: none;
+  flex: 1 1 auto;
+  overflow: auto;
+}
+
 @media (max-width: 980px) {
   .tool-shell-page .tool-shell-container {
     width: min(100%, calc(100% - 16px));