Refactor completion sessions and guarded acceptance (#12)

* chore: prepare Amp orb environment

Amp-Thread-ID: https://ampcode.com/threads/T-01a0a756-606f-7313-99af-4fe371665e12
Co-authored-by: Helge Sverre Hessevik Liseth <helge.sverre@gmail.com>

* refactor: consolidate completion sessions and acceptance

Amp-Thread-ID: https://ampcode.com/threads/T-01a0a756-606f-7313-99af-4fe371665e12
Co-authored-by: Helge Sverre Hessevik Liseth <helge.sverre@gmail.com>

* fix: guard completion acceptance and LSP ranges

Amp-Thread-ID: https://ampcode.com/threads/T-01a0a756-606f-7313-99af-4fe371665e12
Co-authored-by: Helge Sverre Hessevik Liseth <helge.sverre@gmail.com>

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Co-authored-by: Amp <amp@ampcode.com>