[Fix] Azure DevOps connectionData requests always fail with a 400

[daniel-lxs]

Problem

Azure DevOps only serves /_apis/connectionData at preview api-versions. Requesting it with the shared GA version fails on every call:

connectionData api-version=7.1          -> 400 "The -preview flag must be supplied..."
connectionData api-version=7.0          -> 400 (same message)
connectionData api-version=7.1-preview  -> 200 (returns authenticatedUser)

Two features depended on that call and were silently broken:

• Own-comment detection on ADO PR and work item comments: getAdoDeploymentUser threw on every call, so isDeploymentTokenAuthor failed open (a console.warn and false), leaving only the name-prefix check to keep Roomote from reacting to comments it posted itself.
• Reviewer votes: submit_pull_request_review with approve/request_changes resolves the voting identity through the same resource before casting the vote, so ADO reviewer votes always failed.

Fix

A dedicated ADO_CONNECTION_DATA_API_VERSION = '7.1-preview' constant for the two connectionData call sites (packages/ado and packages/sdk), matching the constant apps/web/src/lib/server/auth.ts already uses for its vssps connectionData probe. The shared ADO_API_VERSION stays 7.1 for the GA resources. Test URL assertions now pin the -preview suffix so this cannot regress silently.

Verification

• Reproduced the 400/400/200 matrix above against a real dev.azure.com organization, and ran the fixed getAdoDeploymentUser live: it resolves the deployment identity where it previously threw.
• Confirmed live that the id connectionData returns for a PAT matches the id on the same user's PR-surface activity, so the id branch of isDeploymentTokenAuthor detects Roomote's own comments. (The existing normalizeAdoLinkedAccountKey docblock caveat about vssps vs org identity ids applies to Entra OAuth, not PAT.)
• @roomote/ado suite (41), sdk pull-request-writes tests (13), and all ADO handler tests in apps/api (60) pass; tsc --noEmit clean on both packages.

Context: found as a follow-up to #888, whose credential probe hit the same 400 and deliberately switched to /_apis/git/repositories instead of touching getAdoDeploymentUser.

🤖 Generated with Claude Code

[roomote-roomote]

No code issues found. See task

_{Reviewed 8bd192c}