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/intel/__init__.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Threat-intel enrichment subsystem — out-of-band lookups for attacker IPs.
 
 Sibling to :mod:`decnet.geoip` and :mod:`decnet.asn`, but runs as a

decnet/intel/abuseipdb.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """AbuseIPDB provider.
 
 Endpoint: ``GET https://api.abuseipdb.com/api/v2/check``

decnet/intel/base.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Threat-intel provider protocol.
 
 Each concrete provider (:mod:`decnet.intel.greynoise`,

decnet/intel/factory.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Threat-intel provider factory.
 
 Returns the **list** of configured :class:`IntelProvider` instances —

decnet/intel/feodo.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """abuse.ch Feodo Tracker provider — bulk JSON botnet C2 feed.
 
 Endpoint: ``GET https://feodotracker.abuse.ch/downloads/ipblocklist.json``

decnet/intel/greynoise.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """GreyNoise Community API provider.
 
 Endpoint: ``GET https://api.greynoise.io/v3/community/<ip>``

decnet/intel/mal_hash.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """MalwareBazaar bad-hash provider — bulk SHA-256 feed.
 
 Mirrors :mod:`decnet.intel.feodo` for the refresh / TTL / set-membership

decnet/intel/threatfox.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """abuse.ch ThreatFox provider — per-IOC query API.
 
 Endpoint: ``POST https://threatfox-api.abuse.ch/api/v1/``

decnet/intel/worker.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Long-running threat-intel enrichment worker.
 
 Fans out per attacker IP across the configured intel providers