runtime: the pre-flight resolves the edge the join wrote (ACE-133)

[sandeep-agami]

Spec: ACE-133 (agami-sdlc projects/agami-core-extension/specs/reconcile-evidence/ACE-133-fan-trap-written-edge.md)

Stacked on #318 (ACE-132). Round 9 of the reconcile stack, from the 51-row run.

The finding

"Pre-flight reports fan_trap on a join it elsewhere reports as one-to-one." A subclass view joined to its base table on the key the model declares one_to_one was reported fan_trap on two aggregates by sm prepare, while sm receipt on the identical statement called the join one_to_one. Clearing the finding forced a UNION ALL restructure of a correct statement.

_one_side_facing_many collected every multiplying relationship between the two tables by table pair and never read from_column, to_column or the written ON; co-presence in scope was the whole test. Not "first found": every edge between the pair is unioned, so declaration order cannot help. The receipt's joins section matches by column pairs (_declared_pairs(rel) <= js.pairs), a different algorithm with no shared helper, which is how one receipt contradicted itself. No test declared two usable edges between one pair; test_ace059_join_adherence.py rules the shape out on purpose.

The change

runtime.py

• _written_join_pairs(tree, scope_map): this SELECT's own joins as the column pairs each wrote, keyed by the unordered table pair, under _joined_table_pairs's pinning rule (an ON that names its own join's two relations; an unresolved qualifier contributes nothing).
• _edges_as_written(rels, tree, scope_map, dialect): for a table pair the statement joined with a readable key, when at least one declared edge between them matches that key, only the matching edges stay in the list; otherwise every edge stays. _declared_pairs's None is "does not match", never a wildcard.
• Applied once per arm in _aggregate_reports, before the chasm and fan detectors, so both read one list. _one_side_facing_many and _many_side_facing_one are unchanged.

A join on a key the model does not declare, or two tables in scope with no join between them (CROSS JOIN, a chain through a third table), keep every edge and today's verdict: over-reporting a fan says more than it had to; clearing one on an undeclared key would say something false.

Tests

tests/test_ace060_trap_free_aggregates.py, a new synthetic two-edge fixture (widget, widget_premium_v; one_to_one on id and many_to_one on parent_id, the sibling declared first so a reorder could not pass): the identity join is not_multiplied and the joins section of the same receipt reads declared, one_to_one (red before the change); the sibling join fans and names the join; a join on an undeclared key and a CROSS JOIN keep today's verdict. 507 passed across the trap, receipt, adherence, filter, probes and reconcile end-to-end suites.

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