Eliminate redundant default Lint.swift files fleet-wide

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Outcome

Eliminate redundant “basic/default bundle” Lint.swift files structurally across the Swift Institute fleet and mechanically prevent their reintroduction.

Acceptance

1. Run a positive-controlled census of every tracked root and nested Lint.swift across primitives, standards, and foundations. Record exact blobs plus the effective rule composition each file selects.
2. Partition the population into:
   • semantically identical to the centrally selected layer/default bundle;
   • package-specific composition with a proved owning requirement;
   • malformed, stale, or ambiguous.
3. Remove every file in the first class as one bounded fleet convergence wave. Do not create per-package handwritten replacements.
4. Ensure CI and local tooling select the correct central layer bundle when Lint.swift is absent; prove absence does not weaken or disable lint.
5. Add a mechanical rule with positive, negative, edge, and near-miss fixtures that rejects a package-local Lint.swift whose effective composition merely reproduces the central default.
6. Require every remaining package-specific file to have a finite semantic disposition/owner; no open-ended path exception or arbitrary local configuration is admitted.
7. Run final fleet census proving zero redundant-basic files and unchanged-or-stronger effective diagnostics.

swift-foundations/swift-async#13 is one measured child row, not the scope boundary.

Refs package-reduction programme #527 and lint convergence Goal #90.

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Census receipt (2026-08-11): execution manifest SHA-256 412215977480e55c6de70752447cbc381984b50dd7488cf91b2da85658faa011 was revalidated against the complete 447-row partition: 437 root Lint.swift rows classified remove-redundant-default, 8 package-specific root configurations retained (carrier-primitives, standard-library-extensions, linter-primitives, primitives-linter-rules, standards-linter-rules, institute-linter-rules, swift-linter, swift-linter-rules), and 3 nested production/fixture files held. The census is anchored to the committed inventory revision a35d05385edd8bb957bd00e343ce4e5aecac42d3. Each removal transaction will re-guard the current remote default head and root blob before creating its one-file PR; changed, foreign-bypass, dirty, or ambiguous rows are skipped rather than generalized.

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Structural-wave receipt (2026-08-11): all 437 rows classified remove-redundant-default in census SHA-256 412215977480e55c6de70752447cbc381984b50dd7488cf91b2da85658faa011 are now absent at Lint.swift on the live default branch. The closing remote census returned absent for 437/437 candidates.

Transactions were exact-head, exact-blob, one-file PR diffs; each was squash-merged without CI or bot review. Protected-main bypasses were one-shot and restored/read back to their captured state. The three unprotected repositories used the same branch/PR/file/head guards without any ruleset mutation. Closing transactions: swift-foundations/swift-agent-skills #2 (08b84d660afddcd7507330a112af87406140e5c0), swift-foundations/swift-signature #2 (2f2b4a01095dcd78d350655c5e18c75e06fe3b12), swift-primitives/swift-tagged-primitives #5 (b5f24e2ea54df75dbe42a167f4bc55a71828b19c), and swift-w3c/swift-w3c-xml #4 (c93890ac783b5aabe3f68bf783e08e5097daf31f; bypass restored to []). swift-foundations/swift-async #14 closed #13.

The eight package-specific root configurations remain retained: swift-carrier-primitives, swift-standard-library-extensions, swift-linter-primitives, swift-primitives-linter-rules, swift-standards-linter-rules, swift-institute-linter-rules, swift-linter, and swift-linter-rules. The three nested production/fixture Lint.swift paths remain held and were never treated as package configuration.