refactor: move inline styles to CSS modules

Extract inline fontSize/color styles from LogTab, LayoutShell,
UsersTab, GroupsTab, RolesTab, and LevelFilterBar into CSS modules.
Follows project convention of CSS modules over inline styles.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

ui/src/components/ExecutionDiagram/tabs/LogTab.module.css

@@ -0,0 +1,97 @@
+/* ==========================================================================
+   LOG TAB — STYLES
+   ========================================================================== */
+.container {
+  display: flex;
+  flex-direction: column;
+  height: 100%;
+  min-height: 0;
+}
+
+.filterBar {
+  padding: 6px 10px;
+  border-bottom: 1px solid var(--border-subtle);
+}
+
+.filterInput {
+  width: 100%;
+  padding: 4px 8px;
+  font-size: 12px;
+  border: 1px solid var(--border-subtle);
+  border-radius: var(--radius-sm);
+  background: var(--bg-surface);
+  color: var(--text-primary);
+  outline: none;
+  font-family: var(--font-body);
+}
+
+.logList {
+  flex: 1;
+  overflow-y: auto;
+  font-size: 12px;
+  font-family: var(--font-mono);
+}
+
+.logTable {
+  width: 100%;
+  border-collapse: collapse;
+}
+
+.logRow {
+  border-bottom: 1px solid var(--border-subtle);
+}
+
+.timestampCell {
+  padding: 3px 6px;
+  white-space: nowrap;
+  color: var(--text-muted);
+}
+
+.levelCell {
+  padding: 3px 4px;
+  white-space: nowrap;
+  font-weight: 600;
+  width: 40px;
+}
+
+.levelError {
+  color: var(--error);
+}
+
+.levelWarn {
+  color: var(--warning);
+}
+
+.levelDebug {
+  color: var(--text-muted);
+}
+
+.levelTrace {
+  color: var(--text-faint, var(--text-muted));
+}
+
+.levelDefault {
+  color: var(--text-secondary);
+}
+
+.messageCell {
+  padding: 3px 6px;
+  color: var(--text-primary);
+  word-break: break-word;
+}
+
+.footer {
+  padding: 6px 10px;
+  border-top: 1px solid var(--border-subtle);
+  font-size: 12px;
+  text-align: center;
+}
+
+.openLogsButton {
+  background: none;
+  border: none;
+  color: var(--amber);
+  cursor: pointer;
+  font-size: 12px;
+  font-family: var(--font-body);
+}