[Improve] Simplify Azure DevOps setup

[mrubens]

Related issue

N/A — internal Roomote work requested by a maintainer.

Why this PR exists

• A maintainer explicitly invited this PR in the linked issue or discussion
• I am a maintainer / this is internal Roomote work

What changed

• guide Azure DevOps setup through validated organization entry before PAT creation
• build the PAT creation link from the organization instead of using the broken organization-less URL
• require Microsoft Entra account linking for Azure DevOps Services and immediately start the link flow after saving
• show the exact Azure DevOps OAuth callback, Entra app registration link, and delegated permission guidance
• automatically reuse existing Microsoft sign-in or Teams app credentials, including the stored secret, while keeping Azure DevOps-specific values as overrides
• keep Azure DevOps Server on its PAT-only path and hide unrelated advanced settings by default
• update public Azure DevOps and environment-variable documentation

How it was tested

• 55 focused web Vitest tests covering setup UI, save-and-link behavior, Microsoft credential reuse, auth-provider resolution, ADO helpers, and source-control persistence
• 18 focused @roomote/types Vitest tests covering conditional Azure DevOps Services OAuth requirements and Microsoft aliases
• pnpm lint:fast
• pnpm check-types:fast
• pnpm knip
• git diff --check

Checklist

• The PR title follows the repo convention: [Fix], [Feat], [Improve], [Refactor], [Docs], or [Chore] followed by a user-facing description
• This PR is scoped to the Azure DevOps setup and account-linking flow
• Lint, type checking, and knip pass locally
• I added focused tests
• I removed secrets, tokens, private keys, and customer data from code, logs, and screenshots
• The user-facing change has a changeset

[roomote-roomote]

No new code issues found. See task

_{Reviewed 71948cc}