chore: relicense to AGPL-3.0-or-later and add SPDX headers

Replaces LICENSE (GPLv3 -> AGPLv3) and prepends
`SPDX-License-Identifier: AGPL-3.0-or-later` to every source file
across decnet/, decnet_web/, tests/, scripts/, and tools/.

Rationale: closes the GPLv3 ASP loophole so any party operating a
modified DECNET as a network service must offer their modified
source. Personal copyright (Samuel Paschuan) + inbound=outbound
contributions make a future unilateral relicense infeasible.

- LICENSE: full AGPL-3.0 text (gnu.org/licenses/agpl-3.0.txt)
- COPYRIGHT: project copyright notice
- tools/add_spdx_headers.py: idempotent header injector
  (shebang- and PEP 263-aware)

Touches 1565 source files (.py, .ts, .tsx, .js, .jsx, .css, .sh).
No behavior change; comments only.

tests/topology/__init__.py

@@ -0,0 +1 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later

tests/topology/test_allocator.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Allocator unit + integration tests."""
 from __future__ import annotations
 

tests/topology/test_compose.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """MazeNET compose-generator + teardown-order tests."""
 from __future__ import annotations
 

tests/topology/test_compose_project_isolation.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Each topology runs under its own docker compose project.
 
 The shared ``-p decnet`` project meant that ``--remove-orphans`` on

tests/topology/test_concurrency.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Optimistic-concurrency (version) checks on topology child mutations."""
 from __future__ import annotations
 

tests/topology/test_deploy.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Deploy/teardown integration tests for MazeNET topologies.
 
 Docker-touching paths live behind ``@pytest.mark.live`` per

tests/topology/test_deploy_agent_branch.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Agent-branch routing inside deploy_topology / teardown_topology.
 
 Exercises the target_host_uuid branch added in Step 6.  We never hit a

tests/topology/test_editing.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Pre-deploy mutation repo methods: pending-only, version-aware."""
 from __future__ import annotations
 

tests/topology/test_generator.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """MazeNET generator determinism + DAG shape tests."""
 from __future__ import annotations
 

tests/topology/test_hashing.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Tests for :mod:`decnet.topology.hashing`."""
 from __future__ import annotations
 

tests/topology/test_layout.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Layout coordinate roundtrips for LAN and TopologyDecky."""
 from __future__ import annotations
 

tests/topology/test_mutator.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Step 7 — topology_mutations queue + mutator reconciler branch."""
 from __future__ import annotations
 

tests/topology/test_persistence.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """MazeNET persistence-layer tests: generator → repo → hydrate roundtrip."""
 import pytest
 

tests/topology/test_reaper.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Tests for the orphan topology-resource reaper."""
 from __future__ import annotations
 

tests/topology/test_repo.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Direct async tests for MazeNET topology persistence.
 
 Exercises the repository layer without going through the HTTP stack or

tests/topology/test_repository_protocol.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Verify BaseRepository structurally satisfies TopologyRepository."""
 
 _PROTOCOL_METHODS = {

tests/topology/test_resync_reconcile.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Mutator reconcile loop + deployer.resync_agent_topology.
 
 Covers the last mile of Step 7: once the heartbeat handler flags a

tests/topology/test_service_config.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Per-decky, per-service config roundtrips through persist + compose."""
 from __future__ import annotations
 

tests/topology/test_status.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """MazeNET status state-machine tests.
 
 Every legal transition declared in the plan is permitted; every other

tests/topology/test_validate.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Validator-rule unit tests + deployer precondition integration."""
 from __future__ import annotations