docs(release): make 2.0 notes match final behavior

[frahlg]

Summary:

• remove the superseded claim that fleet reports bypass the relay and use the final Fleet statistics name
• remove the interim claim that the app protocol is not wired into the process
• describe the final last-owner rule: remote removal is blocked, local removal is allowed, demotion is always blocked
• remove stale API route counts that changed as more routes landed

This changes release text only. PR #824 will regenerate the 2.0.0 changelog after merge.

Checks:

• app enrollment and API role/tier tests
• 36 app sharing and fleet web tests
• git diff --check