ah-pdj reconcile: migrate the remaining raw config-presence tests to Configured() Lined Up

Follow-up to ah-jzv, which exported Configured() on every optional config block and migrated the cmd/agenthubd call sites. internal/reconcile was owned by another agent at the time and was deliberately left alone.

ONE REAL DRIFT, not just style — internal/reconcile/reconcile.go:2010, agentsViewLink: 'if av.BaseURL == "" || piSessionID == ""'. A whitespace-only agentsview.base_url is rejected at load, but this raw test also silently ignores a set-but-blank 'machine', producing a deep link that ends in '~pi:' instead of no link at all. Replace with !av.Configured().

CORRECT TODAY, same shape, worth aligning: reconcile.go:1996 ('if r.cfg.Vikunja.WebURL == ""', task-link suppression) and the value reads at publish.go:83/93/114, qa.go:83/203, artifacts.go:77/89. Those are gated upstream by 'r.yonote != nil', which main.go now sets from Configured(), so they are consistent — the cheap hardening is qa.go:83 gaining '&& r.cfg.Yonote.Configured()' so the loop's own predicate matches config's rather than relying on the wiring having done it.

No consumer outside internal/config decides whether an optional block is configured by inspecting raw fields. agentsViewLink emits no link when 'machine' is unset, and a test pins that. ah-jzv's acceptance grep — cfg.<Block>.<Field> != "" outside internal/config — returns nothing.