Suspicious Replicas: add a per-row link to the DDM transfer-errors dashboard

[maany]

Refs the legacy ticket #24 (point 2 from Rod's original request).

Now that the suspicious-replicas page is live (#710 / #781), it would be useful to give each row a direct link to its DDM transfer-errors dashboard. The original ticket was asking for the same thing in the old WebUI.

We already have the building block:

• createDDMDashboardUrl(baseUrl, scope, name, rse) in src/lib/core/utils/ddm-link-utils.ts builds the right URL with the scope/name/rse filters set.
• FEATURE_DDM_DASHBOARD env flag controls whether DDM links show up at all (consistent with how Rule Details and Locks use it).

What we'd like:

• A third action button on each row in the suspicious-replicas table, next to "Declare bad" and "View", that opens the DDM dashboard for that file in a new tab.
• The button should only render when FEATURE_DDM_DASHBOARD is enabled.
• Bulk behaviour is out of scope here, this is per-row only.

Acceptance:

• When FEATURE_DDM_DASHBOARD=true, each row has a "DDM Dashboard" action that opens the right URL.
• When the flag is off, no extra button shows up.
• No new env vars or backend wiring needed beyond what already exists.