fix(packaging): move templates/ into decnet/ package so they ship with pip install

The docker build contexts and syslog_bridge.py lived at repo root, which
meant setuptools (include = ["decnet*"]) never shipped them. Agents
installed via `pip install $RELEASE_DIR` got site-packages/decnet/** but no
templates/, so every deploy blew up in deployer._sync_logging_helper with
FileNotFoundError on templates/syslog_bridge.py.

Move templates/ -> decnet/templates/ and declare it as setuptools
package-data. Path resolutions in services/*.py and engine/deployer.py drop
one .parent since templates now lives beside the code. Test fixtures,
bandit exclude path, and coverage omit glob updated to match.

tests/test_sniffer_ja3.py

@@ -18,7 +18,7 @@ import pytest
 
 # ─── Import sniffer module with mocked syslog_bridge ─────────────────────────
 
-_SNIFFER_DIR = str(Path(__file__).parent.parent / "templates" / "sniffer")
+_SNIFFER_DIR = str(Path(__file__).parent.parent / "decnet" / "templates" / "sniffer")
 
 def _load_sniffer():
     """Load templates/sniffer/server.py with syslog_bridge stubbed out."""

tests/test_ssh_capture_emit.py

@@ -19,7 +19,7 @@ import pytest
 
 from decnet.collector.worker import parse_rfc5424
 
-_TEMPLATE_DIR = Path(__file__).resolve().parent.parent / "templates" / "ssh"
+_TEMPLATE_DIR = Path(__file__).resolve().parent.parent / "decnet" / "templates" / "ssh"
 _EMIT_SCRIPT = _TEMPLATE_DIR / "emit_capture.py"