fix(ci): add SPDX header to REUSE.toml and track proptest regressions

REUSE.toml was missing its own copyright header, failing the REUSE lint
CI job. Also adds proptest regression seeds for safety tests and covers
them with a REUSE annotation glob.

Author: Sephyi

REUSE.toml

@@ -1,3 +1,7 @@
+# SPDX-FileCopyrightText: 2026 Sephyi <me@sephy.io>
+#
+# SPDX-License-Identifier: AGPL-3.0-only OR LicenseRef-Commercial
+
 version = 1
 SPDX-PackageName = "commitbee"
 SPDX-PackageSupplier = "Sephyi <me@sephy.io>"
@@ -37,3 +41,10 @@ precedence = "aggregate"
 SPDX-FileCopyrightText = "2026 Sephyi <me@sephy.io>"
 SPDX-License-Identifier = "AGPL-3.0-only OR LicenseRef-Commercial"
 SPDX-FileComment = "Fuzz testing crate manifest"
+
+[[annotations]]
+path = "tests/*.proptest-regressions"
+precedence = "aggregate"
+SPDX-FileCopyrightText = "2026 Sephyi <me@sephy.io>"
+SPDX-License-Identifier = "AGPL-3.0-only OR LicenseRef-Commercial"
+SPDX-FileComment = "Proptest regression seeds"

tests/safety.proptest-regressions

@@ -0,0 +1,8 @@
+# Seeds for failure cases proptest has generated in the past. It is
+# automatically read and these particular cases re-run before any
+# novel cases are generated.
+#
+# It is recommended to check this file in to source control so that
+# everyone who runs the test benefits from these saved cases.
+cc faba3d9f5e75625263d87d5fc58252fccb0f9b43c7423b3ab1c0fbe9be913683 # shrinks to input = ""
+cc a6030c05a0dddfa68216187ad7d125b2b87d09607379e4e060518f3baf28b037 # shrinks to input = ""