aca-sandboxes skill uses legacy ARM endpoints for connector Swagger and operation discovery

[prjhawar]

Problem

The aca-sandboxes skill uses the legacy ARM endpoints for Swagger and operation discovery:

• managedApis/{connector}/apiOperations?api-version=2016-06-01
• managedApis/{connector}?api-version=2016-06-01&export=true

These should be replaced with the connection's runtime metadata URL (derived from connectionRuntimeUrl by replacing /apim/ with /metadata/ and appending ?export=true).

Issues with the current state

1. Inconsistent with runtime calls — sandbox apps call the runtime URL, but discovery uses a different endpoint
2. Stale Swagger parsing — the Python snippets assume an ARM envelope (data['properties']['apiDefinitions']['value']['paths']) that doesn't match the actual response (raw Swagger at the top level)
3. No outside-sandbox auth guidance — the skill needs to document the API Hub token + user-ACL pattern for early exploration
4. No idempotent ACL pattern — agents recreate ACLs blindly instead of checking first
5. Silent execution — the agent runs shell commands without narrating what it's doing, leaving the user confused about progress

Expected behavior

• Skill consistently uses the metadata URL for all Swagger and operation discovery
• Both inside-sandbox (egress proxy) and outside-sandbox (user-ACL + API Hub token) auth paths are documented
• ACL creation is idempotent (GET first, PUT only if missing)
• Agent announces each step with context (URL, what it's doing, why)

Fix

See #128.