feat(canary): honeydoc_docx + honeydoc_pdf generators

honeydoc previously emitted HTML only — operators picking 'Document'
out of the dropdown got a .html file dropped at /Documents/
quarterly_report.docx, which any attacker would clock the moment they
ran 'file' on it.

Two new generators that emit the real artifact format:

- honeydoc_docx: stdlib zipfile only. Builds a minimal but valid
  Office Open XML zip with the same Q3 review body as the HTML
  flavor and an external-image relationship pointing at the
  callback URL — same trick the operator-upload DOCX instrumenter
  uses, fetched on document open by Word and LibreOffice. Reuses
  _drawing() and _next_rid() from instrumenters/docx.py to keep
  the body/relationships shape identical between synthesised and
  instrumented files.

- honeydoc_pdf: pikepdf-backed. One-page PDF in the 14 base fonts
  (Helvetica, no font embedding), realistic body, /OpenAction /URI
  on the catalog so most viewers fire the callback on document
  open. Falls back to a clear error if pikepdf is missing so the
  operator can switch to honeydoc / honeydoc_docx.

Default placement paths now reflect each generator's true extension
(.html / .docx / .pdf) so the UI suggests something sensible. Both
generators surfaced in the New Token modal's generator dropdown.

decnet/canary/factory.py

@@ -18,6 +18,8 @@ KNOWN_GENERATORS: Tuple[str, ...] = (
     "ssh_key",
     "aws_creds",
     "honeydoc",
+    "honeydoc_docx",
+    "honeydoc_pdf",
 )
 
 KNOWN_INSTRUMENTERS: Tuple[str, ...] = (
@@ -52,6 +54,12 @@ def get_generator(name: str) -> CanaryGenerator:
     if name == "honeydoc":
         from decnet.canary.generators.honeydoc import HoneydocGenerator
         return HoneydocGenerator()
+    if name == "honeydoc_docx":
+        from decnet.canary.generators.honeydoc_docx import HoneydocDocxGenerator
+        return HoneydocDocxGenerator()
+    if name == "honeydoc_pdf":
+        from decnet.canary.generators.honeydoc_pdf import HoneydocPdfGenerator
+        return HoneydocPdfGenerator()
     raise ValueError(
         f"Unknown canary generator: {name!r}. Known: {KNOWN_GENERATORS}"
     )