fix: review-bot findings on the provider-hosted shell

- Keep ConversationSession mounted for blank sessions (chrome-less) so the
  draft-persistence mirror stays bound in the hero; hero typing reaches the
  chat store again.
- Restore the baselines-ready gate in AppFrame: empty boot snapshots no
  longer flash the New Workspace hero before either baseline lands.
- Commit ordinary sends through the machine (send-committed event +
  Shell.commitSend): undo can no longer resurrect already-sent content on
  the default-sink path.
- Give the production InputMachine a real wall clock so the typing-run
  merge window actually expires.
- Coalesce concurrent connectWorkspace creates per workspace: the summary
  has no cwd until the host frame lands, so a second New Session inside
  that window minted a duplicate hidden blank session.

packages/client/ui-conversation/src/client/input/machine.ts

@@ -167,6 +167,7 @@ export class InputMachine {
       case 'adjudicated': return this.onAdjudicated(ev.attempt, ev.outcome)
       case 'adjudication-failed': return this.onAdjudicationFailed(ev.attempt, ev.message)
       case 'submit-settled': return this.onSubmitSettled(ev)
+      case 'send-committed': return this.onSendCommitted()
       case 'release': return this.onRelease()
       default: return unreachable(ev)
     }
@@ -542,6 +543,19 @@ export class InputMachine {
     return [{ type: 'notice', level: 'error', text }]
   }
 
+  /** Ordinary send accepted: clear as a commit (no undo unit; sent content
+   *  must not be resurrectable — same discipline as submit-settled success). */
+  private onSendCommitted(): InputEffect[] {
+    this.claim = undefined
+    this.occurrences = []
+    this.adopt('')
+    this.log = []
+    this.redoStack = []
+    this.typingRun = undefined
+    this.paste = undefined
+    return []
+  }
+
   private onRelease(): InputEffect[] {
     if (this.inflight !== undefined) {
       this.inflight.controller.abort()