Package agentic-ops for gh aw add owner/repo installation

[Copilot]

This PR aligns the repository with the gh-aw package format so consumers can install the workflow bundle directly from the repo root. It introduces a package manifest and updates onboarding docs to match package-based consumption.

• Package manifest

  • Adds root-level aw.yml with package metadata and explicit installable workflow entries.
  • Declares the three shared workflows under workflows/ as the package surface.

• Consumer install flow

  • Updates README.md Quick Start to use a single package install command (gh aw add githubnext/agentic-ops) instead of individual workflow sources.
  • Clarifies repository-root package layout and required post-install usage (gh aw compile).
  • Adds concise prerequisites and configuration notes for adopters.

# aw.yml
manifest-version: "1"
name: agentic-ops
description: Reusable agentic workflows for auditing and optimizing workflow token usage.
files:
  - workflows/agentic-token-audit.md
  - workflows/agentic-token-optimizer.md
  - workflows/daily-subagent-optimizer.md