[Feat] Add linked identities for source-control providers

[roomote-roomote]

Opened on behalf of @mrubens.

What changed

• Persist host-scoped, provider-verified identities for linked GitLab, Gitea, Bitbucket, and Azure DevOps accounts.
• Preserve configured non-default ports in identity host keys so self-hosted provider accounts match their repositories.
• Show verified handles or display names in Personal Settings instead of opaque provider account IDs.
• Use verified public handles for public pull request attribution while keeping email-derived and unverified identities generic.
• Use GitLab.com's verified noreply identity for public commits; other non-GitHub providers keep the Roomote Git identity when no safe provider address exists.
• Keep private attribution human-readable and fail closed for unknown or mixed source-control hosts.

Why this change was made

Non-GitHub account links previously retained only opaque OAuth account IDs, so Roomote could not provide useful account display or privacy-safe public attribution equivalent to GitHub. Provider profile mappings make that identity durable without deriving handles from private email addresses.

Impact

Users see recognizable linked source-control identities in Settings. Public GitLab, Gitea, and supported Bitbucket changes can credit a verified handle; Azure DevOps and any unverified or ambiguous identity remain attributed to Roomote. Existing links populate the mapping after token refresh or relinking, including links to providers configured on non-default ports.

[roomote-community]

No new code issues found. See task

• apps/web/src/lib/server/auth.ts:512 Preserve non-default ports in host-scoped identity keys so linked identities match their repositories.

_{Reviewed 2443392}