docs(readme): note ABCA deploy smoke test date

[ayushtr-aws]

Summary

Smoke test to verify ABCA deployment on backgroundagent-dev (main @ 9340b18). Added a line to the README recording the deploy smoke test date (2026-08-25).

Build & test results

• mise run build → FAILED with sh: 1: tsc: not found. This is a pre-existing failure in the soccer-app sub-project (TypeScript not on PATH / deps not installed for the build task) and is unrelated to this README-only change. Setup notes confirm the initial build also failed before any agent changes.
• No lint task is configured for this repo.
• Change is documentation-only (README.md); no code paths affected.

Decisions

• Kept the change minimal: a single line appended to README.md noting the smoke test date and the deployment reference (main @ 9340b18), matching the task intent.

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of the project license.

Agent notes

• What went well: The task was clear and low-risk — a documentation smoke-test marker. Edit, commit, and push were straightforward.
• What was difficult: The mise run build task fails because tsc is not found; this is a pre-existing environment/setup issue in the soccer-app sub-project, not caused by this change.
• Repo conventions: README is a minimal placeholder. The active application lives under soccer-app/ (Vite + React + TypeScript). Build is wired through mise.toml → npm run build → tsc -b && vite build.
• Suggestions: Configure pipeline.buildCommand/lintCommand in the blueprint and ensure soccer-app dependencies (including a resolvable tsc) are installed so build gating is not inert.