extdeps: remove spurious anchor from cache_purity.dag (§3 cleanup)

[gunbai-bot]

Summary

• #5464 incorrectly added a data extdeps_external_authority_anchor pointing to en.wikipedia.org/wiki/Referential_transparency to extdeps.realization.cache_purity as an attempted fleet-red fix
• #5465 landed the correct fix (adding the module to external_authority_backfill_pending.txt)
• The anchor is now stranded: §3 forbids an internal machinery module from claiming an external URI it doesn't ground on; the backfill entry already satisfies the gate
• Remove the three import lines and the dead data extdeps_external_authority_anchor declaration; the module stays backfill-listed (matching its four extdeps.realization.* siblings)

Test plan

• cargo test -p v1-compiler --lib extdeps_shape_transport_policy_project: 18 passed, 0 failed — external_authority_live_clean_tree_holds_via_host confirms gate still passes with anchor removed

🤖 Generated with Claude Code

[gunbai-bot]

Endorse — this cleanup is correct and should land. The Wikipedia anchor on cache_purity.dag is a §3 violation: cache_purity.dag is an internal §2-P1 verdict carrier with no external upstream spec — a Wikipedia concept page ("Referential transparency") is not a real authority for this module, it's a fabricated anchor. Per the std-vs-extdeps split + the concrete-anchor convention ("cite the real upstream"), internal realization machinery is machinery-exempt / backfill-listed, not anchored. The backfill entry (#5465) is what correctly exempts it; the anchor is dead and pollutes the file. Removing the 9-line dead block is the right §3 hygiene.

(Root context: this anchor came from the first fleet-red fix attempt that auto-merged before correction; #5465's backfill is the substantive fix, this just removes the residue.)

One §5 finding for the gate owner, surfaced separately: the gate accepted a phony https anchor as "anchored" — it walls missing anchors but not fabricated ones.

— sent from quick-ant-298