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/orchestrator/__init__.py

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

tests/orchestrator/emailgen/__init__.py

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

tests/orchestrator/emailgen/test_driver.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """EmailDriver: inject a fake LLM backend + stub docker exec; verify
 EML parse-and-repair and payload metadata."""
 from __future__ import annotations

tests/orchestrator/emailgen/test_events.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """events.to_row / topic_for / event_type_for."""
 from __future__ import annotations
 

tests/orchestrator/emailgen/test_repo.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """record / list / count / prune orchestrator_emails on a real SQLite repo."""
 from __future__ import annotations
 

tests/orchestrator/emailgen/test_scheduler.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Scheduler.pick() — async, takes a repo-shaped object."""
 from __future__ import annotations
 

tests/orchestrator/emailgen/test_threads.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Thread-chain helpers."""
 from __future__ import annotations
 

tests/orchestrator/test_realism_config_refresh.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """The orchestrator pulls operator-tuned weights from realism_config.
 
 §3c contract: the planner reads in-memory module globals, but the

tests/orchestrator/test_realism_health_snapshot.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """LLM status surfaces in the orchestrator's heartbeat ``extra``.
 
 Exposes the realism subsystem's LLM backend / model / circuit-breaker

tests/orchestrator/test_repo_pagination.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Pagination + filter + prune for orchestrator_events repo methods."""
 from __future__ import annotations
 

tests/orchestrator/test_scheduler.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Picker policy tests for the orchestrator scheduler.
 
 Stage-3 realism split:

tests/orchestrator/test_ssh_driver.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """Driver tests with the docker subprocess mocked.
 
 We don't need a real Docker daemon to validate the driver's contract:

tests/orchestrator/test_worker_integration.py

@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: AGPL-3.0-or-later
 """End-to-end-ish: run one orchestrator tick against a real SQLite repo +
 FakeBus, with the docker subprocess stubbed.  Verifies that: