[FSSDK-12221] Agent dev docs bash (#461)

* [FSSDK-12221] Update README.md documentation links and fix errors

- Update all documentation URLs from v4.0.0-full-stack to feature-experimentation
- Fix webhook port default from 8085 to 8089 (matches config.yaml)
- Fix typos: 'promethues' -> 'prometheus'
- Fix grammar: 'two type' -> 'two types'
- Fix grammar: "it's own" -> "its own"

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

* [FSSDK-12221] Update examples/README.md

- Fix typo: 'superseeded' -> 'superseded'
- Fix typo: 'requests' -> 'request'
- Update auth.md reference to point to online Authorization Guide docs

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

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Co-authored-by: Claude Sonnet 4.5 <noreply@anthropic.com>

Author: Mat001