chore: prepare av-tools 0.3.0 release

SOURCE.md

@@ -1,6 +1,6 @@
 # Source and reproducibility record
 
-This file identifies the source corresponding to av-tools 0.2.1. It is not a
+This file identifies the source corresponding to av-tools 0.3.0. It is not a
 substitute for satisfying a component's licence or for delivering complete
 Corresponding Source with an object-code release.
 
@@ -9,9 +9,9 @@ Corresponding Source with an object-code release.
 - Canonical repository:
   `git@git.add-ideas.de:lotobo/av-tools.git`
 - Browser source: `https://git.add-ideas.de/lotobo/av-tools`
-- Version: `0.2.1`
-- Release source identity: immutable annotated tag `v0.2.1`
-  (`refs/tags/v0.2.1`) in the canonical repository.
+- Version: `0.3.0`
+- Release source identity: immutable annotated tag `v0.3.0`
+  (`refs/tags/v0.3.0`) in the canonical repository.
 - Application licence: `GPL-3.0-or-later`; full GPL version 3 terms in
   `LICENSE`.
 - Copyright: Copyright © 2026 Albrecht Degering.
@@ -22,10 +22,10 @@ the tag exists, is annotated, points to the reviewed release commit and is
 available without authentication:
 
 ```sh
-test "$(git cat-file -t v0.2.1)" = tag
-git rev-parse v0.2.1^{commit}
+test "$(git cat-file -t v0.3.0)" = tag
+git rev-parse v0.3.0^{commit}
 git ls-remote --tags \
-  https://git.add-ideas.de/lotobo/av-tools.git refs/tags/v0.2.1
+  https://git.add-ideas.de/lotobo/av-tools.git refs/tags/v0.3.0
 ```
 
 The Toolbox manifest names the canonical repository and SPDX licence. Publish