fix: QA regression pass — graph sizing, focus trap, contrast, accessibility

- Fix graph canvas using window dimensions instead of container by using
  ResizeObserver ref callback (attaches when conditionally-rendered
  container mounts)
- Fix dialog focus trap escaping to background — filter hidden/disabled
  elements from focusable selector
- Fix sidebar connection status and disconnection banner contrast — use
  semantic text-warning/bg-warning instead of amber-400 (1.65:1 → 4.5:1+)
- Add aria-label to chat textarea, htmlFor/id pairs to flows dialog inputs
- Add ARIA tab pattern to prompts page (role=tablist/tab/tabpanel,
  aria-selected, aria-controls)
- Fix prompts heading hierarchy (H1→H2 instead of H1→H3)
- Add flex-wrap to flows page header, fix badge contrast across pages
- Fix service-call race condition with early returns instead of console.log

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

ts/packages/client/src/socket/service-call.ts

@@ -76,9 +76,8 @@ export class ServiceCall {
    * @param resp - The response object received from the server
    */
   onReceived(resp: object) {
-    // Defensive check - this shouldn't happen but log if it does
-    if (this.complete == true)
-      console.log(this.mid, "should not happen, request is already complete");
+    // Guard: ignore duplicate responses after completion
+    if (this.complete) return;
 
     // Mark as complete to prevent duplicate processing
     this.complete = true;
@@ -151,12 +150,8 @@ export class ServiceCall {
    * Triggers another attempt if retries are available
    */
   onTimeout() {
-    // Defensive check - this shouldn't happen but log if it does
-    if (this.complete == true)
-      console.log(
-        this.mid,
-        "timeout should not happen, request is already complete",
-      );
+    // Guard: ignore timeout after completion
+    if (this.complete) return;
 
     console.log("Request", this.mid, "timed out");
 
@@ -184,12 +179,8 @@ export class ServiceCall {
    * Handles retries and waits for BaseApi to handle reconnection
    */
   attempt() {
-    // Defensive check - this shouldn't be called on completed requests
-    if (this.complete == true)
-      console.log(
-        this.mid,
-        "attempt should not be called, request is already complete",
-      );
+    // Guard: don't retry completed requests
+    if (this.complete) return;
 
     // Decrement retry counter
     this.retries--;