docs(provenance): clarify approved Classic reuse

AGENTS.md

@@ -17,6 +17,21 @@
 - New Python work must document its supported runtime and dependencies. Do not
   duplicate client/server command IDs in packet-aware tools; consume a released
   protocol binding when such tooling becomes maintained here.
+- Source in this repository remains GPL as distributed under `COPYING`. That
+  is not a blanket outbound reuse ban. Under the
+  [canonical provenance policy](https://github.com/atrinik/atrinik/blob/main/docs/PROVENANCE.md),
+  an MIT destination may inspect exact, independently separable material as
+  source reference, copy it, migrate or port it, translate or adapt it, or
+  relicense it only after a complete audit proves each selected contribution
+  is the applicable named grantor's original work. Each contribution must be
+  solely authored by that grantor and fall within the row's temporal scope.
+  Distinct contributions may cite different rows only when each independently
+  satisfies one row. Rows cannot be combined to cover jointly authored
+  contributions, generated output, or inseparable mixed work. Later material
+  needs contemporaneous compatible permission. The grants authorize only
+  proven destination use. They neither change this repository's source license
+  nor by themselves approve a GPL dependency, linked or combined binary,
+  bundle, or surrounding material.
 - Autonomous gameplay testing belongs in the independent
   [`atrinik/playtester`](https://github.com/atrinik/playtester) repository; do
   not add bot implementation or mutable bot state here.

CONTRIBUTING.md

@@ -7,4 +7,17 @@ tools, and keep autonomous gameplay testing in the independent
 [`atrinik/playtester`](https://github.com/atrinik/playtester) repository.
 Preserve the GNU General Public License terms in `COPYING`. A new, independently
 authored utility may use the MIT License when feasible, but it must carry a
-clearly scoped license and must not relicense the extracted GPL utilities.
+clearly scoped license. Existing source remains GPL as distributed; that is not
+a blanket outbound reuse ban. Exact, independently separable material may be
+inspected as source reference, copied, migrated or ported, translated or
+adapted, or relicensed in an MIT destination only after the
+[canonical provenance audit](https://github.com/atrinik/atrinik/blob/main/docs/PROVENANCE.md)
+proves each selected contribution is the applicable named grantor's original
+work. Each contribution must be solely authored by that grantor and fall within
+the row's temporal scope. Distinct contributions may cite different rows only
+when each independently satisfies one row. Rows cannot be combined to cover
+jointly authored contributions, generated output, or inseparable mixed work.
+Later material needs contemporaneous compatible permission. The grants
+authorize only proven destination use. They neither change this repository's
+source license nor by themselves approve a GPL dependency, linked or combined
+binary, bundle, or surrounding material.

README.md

@@ -46,4 +46,16 @@ generated bindings for the protocol generation they implement.
 ## License
 
 The extracted source retains its existing GNU General Public License terms.
-See [COPYING](COPYING).
+See [COPYING](COPYING). Those terms are not a blanket outbound reuse ban:
+under the
+[canonical provenance policy](https://github.com/atrinik/atrinik/blob/main/docs/PROVENANCE.md),
+an MIT destination may inspect exact, independently separable material as
+source reference, copy it, migrate or port it, translate or adapt it, or
+relicense it only after the canonical audit proves each selected contribution
+is the applicable named grantor's original work. Each contribution must be
+solely authored by that grantor and fall within the row's temporal scope.
+Distinct contributions may cite different rows only when each independently
+satisfies one row. Rows cannot be combined to cover jointly authored
+contributions, generated output, or inseparable mixed work. Later material needs
+contemporaneous compatible permission. This does not change the source license
+here or approve a GPL dependency or bundle.