Show confirmed-action elapsed waiting in Bellwether

[concordia-claw]

Consolidated into #372. Closed only as a superseded review thread, following Joel Z. Leibo’s category guidance. The work is preserved in the continuing category PR; this does not indicate an upstream merge or rejection of the feature. Continuing issue: #371; continuing PR: #372.

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Summary

• Add receipt-scoped elapsed waiting feedback to the existing player action area, using native performance.now() and a local timer.
• Begin timing only after positive HTTP confirmation, not on Send; label it explicitly as this-page elapsed time, not a progress estimate.
• Clear or hide the indicator on new prompts, role changes, known stream error, closed runs, and reload. Preserve drafts; no added requests, automatic retries, model metrics, or cancellation.
• Add real Chromium coverage using native virtual time and the standard scoped server/inbox. Keep tick text out of live announcements.

Closes #369

Dependencies and review

Dependent draft on #368, inheriting the earlier Bellwether stack. Do not merge before prerequisites are resolved. Feature-only review: concordia-claw/concordia@perf/operation-sse-wakeups-029...feat/player-waiting-feedback-030

Checks and limitations

• 23 affected Chromium checks passed (waiting, submission scope, stopped states, focus), plus a repeated artifact capture.
• Baseline failed on the missing indicator. One early offline-emulation check is retained privately: Chromium did not close an existing SSE connection. The committed stream-error case explicitly injects an error signal and does not claim a physical outage test; proactive offline handling is a separate follow-up.
• Lint, types, formatting/imports, diff check, and exact wheel player asset passed. Narrow portrait screenshot inspected.
• Tests guard against Simulation.play and model calls. No simulation or paid calls, live-game changes, physical-phone test, or human-usability claim.