docs: Adds ADR on the migration to UUID7

[nathanbogale]

Related Issue(s)

Resolves #1369

Description of Changes

This PR introduces a new Architecture Decision Record (ADR) documenting our decision to transition from ULIDs to UUIDv7 for time-ordered identifiers, while using UUIDv4 for non-time-ordered identifiers. The ADR outlines the rationale, implementation guidelines, and migration strategy for this architectural change.

Breaking Changes

While the ADR itself doesn't introduce breaking changes, the implementation of this decision will require:

• Gradual migration of existing ULID implementations to UUIDv7
• Updates to database schemas using UUID types
• Changes to API contracts and documentation
• Updates to identifier generation logic in various services

[x] My code follows the style guidelines of this project
[x] I have performed a self-review of my code
[x] I have commented my code, particularly in hard-to-understand areas
[x] I have made corresponding changes to the documentation
[x] My changes generate no new warnings
[x] I have added tests that prove my fix is effective or that my feature works
[x] New and existing unit tests pass locally with my changes
[x] Any dependent changes have been merged and published in downstream modules

[github-actions]

✅ Test Report | ${\color{lightgreen}Pass: 334/334}$ | ${\color{red}Fail: 0/334}$ |

[github-actions]

✅ Test Report | ${\color{lightgreen}Pass: 334/334}$ | ${\color{red}Fail: 0/334}$ |

[github-actions]

✅ Test Report | ${\color{lightgreen}Pass: 334/334}$ | ${\color{red}Fail: 0/334}$ |

[Mr-Leshiy]

lgtm