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.

decnet/templates/postgres/server.py

@@ -0,0 +1,119 @@
+#!/usr/bin/env python3
+"""
+PostgreSQLserver.
+Reads the startup message, extracts username and database, responds with
+an AuthenticationMD5Password challenge, logs the hash sent back, then
+returns an error. Logs all interactions as JSON.
+"""
+
+import asyncio
+import os
+import struct
+from syslog_bridge import syslog_line, write_syslog_file, forward_syslog
+
+NODE_NAME = os.environ.get("NODE_NAME", "pgserver")
+SERVICE_NAME   = "postgres"
+LOG_TARGET = os.environ.get("LOG_TARGET", "")
+PORT = int(os.environ.get("PORT", "5432"))
+def _error_response(message: str) -> bytes:
+    body = b"S" + b"FATAL\x00" + b"M" + message.encode() + b"\x00\x00"
+    return b"E" + struct.pack(">I", len(body) + 4) + body
+
+
+
+
+def _log(event_type: str, severity: int = 6, **kwargs) -> None:
+    line = syslog_line(SERVICE_NAME, NODE_NAME, event_type, severity, **kwargs)
+    write_syslog_file(line)
+    forward_syslog(line, LOG_TARGET)
+
+
+class PostgresProtocol(asyncio.Protocol):
+    def __init__(self):
+        self._transport = None
+        self._peer = None
+        self._buf = b""
+        self._state = "startup"
+
+    def connection_made(self, transport):
+        self._transport = transport
+        self._peer = transport.get_extra_info("peername", ("?", 0))
+        _log("connect", src=self._peer[0], src_port=self._peer[1])
+
+    def data_received(self, data):
+        self._buf += data
+        self._process()
+
+    def _process(self):
+        if self._state == "startup":
+            if len(self._buf) < 4:
+                return
+            msg_len = struct.unpack(">I", self._buf[:4])[0]
+            if msg_len < 8 or msg_len > 10_000:
+                self._transport.close()
+                self._buf = b""
+                return
+            if len(self._buf) < msg_len:
+                return
+            msg = self._buf[:msg_len]
+            self._buf = self._buf[msg_len:]
+            self._handle_startup(msg)
+        elif self._state == "auth":
+            if len(self._buf) < 5:
+                return
+            msg_type = chr(self._buf[0])
+            msg_len = struct.unpack(">I", self._buf[1:5])[0]
+            if msg_len < 4 or msg_len > 10_000:
+                self._transport.close()
+                self._buf = b""
+                return
+            if len(self._buf) < msg_len + 1:
+                return
+            payload = self._buf[5:msg_len + 1]
+            self._buf = self._buf[msg_len + 1:]
+            if msg_type == "p":
+                self._handle_password(payload)
+
+    def _handle_startup(self, msg: bytes):
+        # Startup message: length(4) + protocol_version(4) + params (key=value\0 pairs)
+        if len(msg) < 8:
+            return
+        proto = struct.unpack(">I", msg[4:8])[0]
+        if proto == 80877103:  # SSL request
+            self._transport.write(b"N")  # reject SSL
+            return
+        params_raw = msg[8:].split(b"\x00")
+        params = {}
+        for i in range(0, len(params_raw) - 1, 2):
+            k = params_raw[i].decode(errors="replace")
+            v = params_raw[i + 1].decode(errors="replace") if i + 1 < len(params_raw) else ""
+            if k:
+                params[k] = v
+        username = params.get("user", "")
+        database = params.get("database", "")
+        _log("startup", src=self._peer[0], username=username, database=database)
+        self._state = "auth"
+        salt = os.urandom(4)
+        auth_md5 = b"R" + struct.pack(">I", 12) + struct.pack(">I", 5) + salt
+        self._transport.write(auth_md5)
+
+    def _handle_password(self, payload: bytes):
+        pw_hash = payload.rstrip(b"\x00").decode(errors="replace")
+        _log("auth", src=self._peer[0], pw_hash=pw_hash)
+        self._transport.write(_error_response("password authentication failed"))
+        self._transport.close()
+
+    def connection_lost(self, exc):
+        _log("disconnect", src=self._peer[0] if self._peer else "?")
+
+
+async def main():
+    _log("startup", msg=f"PostgreSQL server starting as {NODE_NAME}")
+    loop = asyncio.get_running_loop()
+    server = await loop.create_server(PostgresProtocol, "0.0.0.0", PORT)  # nosec B104
+    async with server:
+        await server.serve_forever()
+
+
+if __name__ == "__main__":
+    asyncio.run(main())