fix: replace deprecated Slack actions with mrkdwn link field

[Siumauricio]

What is this PR about?

The actions array in Slack attachments requires Interactive Components to be configured on the Slack app, which causes notifications to fail silently. This replaces the deprecated actions buttons with a Details field using Slack mrkdwn hyperlink syntax (<url|text>) and adds mrkdwn_in: ["fields"] so the link renders as clickable.

Supersedes #4054 (same fix but with the missing mrkdwn_in that PR lacked).

Checklist

• You created a dedicated branch based on the canary branch.
• You have read the suggestions in the CONTRIBUTING.md file https://github.com/Dokploy/dokploy/blob/canary/CONTRIBUTING.md#pull-request
• You have tested this PR in your local instance. If you have not tested it yet, please do so before submitting. This helps avoid wasting maintainers' time reviewing code that has not been verified by you.

Issues related (if applicable)

closes #4053

Screenshots (if applicable)

N/A

Greptile Summary

This PR fixes Slack build notifications by replacing the deprecated actions button array (which requires Interactive Components to be configured on the Slack app) with a Details field using Slack mrkdwn hyperlink syntax (<url|text>), and adds mrkdwn_in: ["fields"] to enable link rendering. The fix is applied consistently in both build-error.ts and build-success.ts; no other notification files used the deprecated pattern.

Confidence Score: 5/5

Safe to merge — fixes silent Slack notification failures with no regression risk.

The change is minimal, targeted, and correct. Both changed files are updated consistently with proper Slack mrkdwn field syntax (<url|text>) and the required mrkdwn_in: ["fields"] property. No P0/P1 issues found.

No files require special attention.

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