Refactor interproc facts domain

[wolfy-j]

Summary

• flash-migrate checker fact/event ownership to the canonical abstract interpreter shape: abstract/trace evidence, abstract/transfer lowering, domain/interproc product facts, and canonical FunctionFacts
• remove the old flowbuild/factproduct production shape, snapshot-style fact inputs, legacy helper rescans, and compatibility projections
• tighten soundness around parameter evidence, iterator transfer, field probes, dynamic any, and function-fact convergence
• add regression coverage for field probes, channel-select/helper returns, recursive schema writes, iterator evidence, gradual typing, and external false-positive cases
• keep INTERPROC_FACTS_DOMAIN_JOURNAL.md updated with the design invariants, DNF/solver boundary, remaining source-proof classifications, and verification checkpoints

Verification

• go test ./compiler/check/... ./types/flow/... -count=1
• go test ./... -count=1
• git diff --check
• /tmp/wippy-local-replace-current-bin lint --cache-reset --no-color --ns app.test.temporal.tests --limit 120 in local-replace tests/app: clean
• /tmp/wippy-local-replace-current-bin lint --cache-reset --no-color --limit 120 --summary in local-replace slices: remaining diagnostics classified as source/proof obligations, not engine false positives
• go run /tmp/debug_soft.go
• ../scripts/verify-suite.sh: go-lua checker tests pass and Wippy binary builds; script still exits non-zero on external pinned lint targets (session, agent, docker-demo)