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.

decnet/topology/__init__.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """MazeNET — nested deception topologies.
 
 A topology is an arbitrary-depth DAG of LANs, connected by multi-homed

decnet/topology/allocator.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """IP and subnet allocators for MazeNET topologies.
 
 Extracted from :mod:`decnet.topology.generator` so the same primitives

decnet/topology/compose.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Compose-file generator for a MazeNET topology.
 
 Produces a ``docker-compose.yml`` dict given a hydrated topology

decnet/topology/config.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """MazeNET topology config + in-memory generation output."""
 from __future__ import annotations
 

decnet/topology/generator.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """MazeNET topology generator.
 
 Produces a :class:`GeneratedTopology` — an in-memory DAG of LANs and

decnet/topology/hashing.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Canonical hash of a hydrated topology dict.
 
 Both master and agent need to agree on "is the applied state the one

decnet/topology/persistence.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Adapter between :class:`GeneratedTopology` and the repository layer."""
 from __future__ import annotations
 

decnet/topology/repository.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 from __future__ import annotations
 
 from typing import Any, Optional, Protocol

decnet/topology/status.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """MazeNET topology status state machine.
 
 Seven states — six active in v1.  ``degraded`` is schema-reserved for the

decnet/topology/validate.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Pre-deploy validator for MazeNET topologies.
 
 Consumes a hydrated dict (output of