fix(types): P3 — annotate transport in all template protocol servers; 0 errors in templates/

- asyncio.Protocol (TCP): _transport: asyncio.Transport | None = None + cast() in
  connection_made; assert guards in every method that directly accesses the field.
  Files: pop3, smtp, mqtt, postgres, mssql, mongodb, imap, ldap, redis, mysql, sip, vnc.
- asyncio.DatagramProtocol (UDP): _transport: asyncio.DatagramTransport | None = None.
  Files: snmp, tftp, SIPUDPProtocol.
- RDP: assert new_transport is not None after start_tls() to narrow Transport | None.
- FTP (Twisted): assert self.transport is not None + targeted type: ignore for imprecise
  Twisted stubs (misc/override/arg-type/attr-defined), IReactorTCP cast for listenTCP.
- conpot: proc.stdout is None guard before iteration.
- Bonus fixes surfaced by annotation:
  - smtp: get_payload(decode=True) bytes narrowing (arg-type on sha256)
  - postgres: rename shadowed `msg` param to `err_msg` in _handle_startup
  - mongodb: base64.binascii.Error → import binascii; binascii.Error
  - imap: result: list[int] = [] (var-annotated)

development/STATIC-TYPES.md

@@ -178,4 +178,14 @@ Enable `check_untyped_defs = true` as the final step once the repo is clean.
   - Remove 9 stale `# type: ignore` comments across logging, helpers, credentials
   - Fix `telemetry.py` overload `no-redef` + `misc`
   - Fix `logs.py` `datetime/str` operator errors and nullable PK comparison
-- [ ] Annotate `transport` in template servers + guard call sites (P3, ~100 errors)
+- [x] P3 — template servers now have 0 mypy errors (146 fixed):
+  - Add `_transport: asyncio.Transport | None` class-level annotation + `cast()` in `connection_made` for 11 TCP Protocol files (pop3, smtp, mqtt, postgres, mssql, mongodb, imap, ldap, redis, mysql, sip, vnc)
+  - Add `_transport: asyncio.DatagramTransport | None` for 2 UDP DatagramProtocol files (snmp, tftp) + SIPUDPProtocol
+  - `assert self._transport is not None` guards in each method that directly accesses transport
+  - Fix RDP `start_tls()` `Transport | None` narrowing with `assert new_transport is not None`
+  - Fix FTP Twisted stubs: `assert self.transport is not None`, `# type: ignore[misc/override/arg-type/attr-defined]` for imprecise Twisted stubs, `IReactorTCP` cast for `listenTCP`
+  - Fix conpot `proc.stdout is None` guard before iteration
+  - Fix SMTP `get_payload(decode=True)` → explicit `bytes` narrowing
+  - Fix postgres `_handle_startup` param-name shadowing (`msg` bytes → `err_msg` str)
+  - Fix mongodb `base64.binascii.Error` → `import binascii; binascii.Error`
+  - Fix imap `result: list[int] = []` var-annotated