A drain can always declare a real interaction

[sameera]

As a delivery lead running a drain, I want the instruction surfaces to stop treating the
cap as a reason to drop an interaction, so that a real edge is recorded as an edge instead of
being demoted to prose on one side.

Acceptance Criteria

• Given a delta that adds a touches edge to the store's highest-degree page, when the
  drain runs the reciprocity fan-out and then the validator, then the reciprocal bullet is
  written and the run passes with no split and no eviction.
• Given each of the three pages PR distill: Backlog Stubs Become GitHub Issues (#185) #219 could not link into, when a reciprocal bullet is
  added to it, then the validator passes it with no split and no eviction.
• Given a page whose own content would overflow the cap after patching, when the drain
  applies the delta, then the split path still fires as before.
• Given the distiller's instructions, then no surface directs dropping, demoting to
  prose, or compressing an interaction in order to fit the cap.
• Given a validator run whose only output is advisories, when the drain evaluates it,
  then the drain proceeds — the "any finding blocks" rule names advisories as the exception.
• Given the concept store's usage README, then its list of what the validator checks
  names the counted region as the page's own content and includes the per-bullet bound.
• Given the eviction-of-last-resort path, then its stated trigger is a page whose own
  content overflows the cap, and neighbour-list pressure is not a trigger for it.

Notes

• story_type: user · size: M

The surfaces that state the current rule are the distiller's page-patching step, its split step,
its reciprocity fan-out step, its validator step (which today reads "any finding from either
command blocks"), and the concept store's usage README. They must agree with the schema after
#221 and with the validator after #222 and #223, which is what makes this
the M of the set.

The three pages PR #219 could not link into are the reciprocal targets its reviewer notes named as
blocked by the cap.