Copy the full-data packet once per report, not once per domain (issue #122, BUG-1471)

read_full_data_domain deep-copied the shared worksheets on every call; a long
report reads five domains twice, so ten copies for read-only use. The shared
part is now copied once (full_data_domain_base) and reused for every domain's
facts and their leaf check; each domain's facts are still copied out so domains
share no objects. Long reports byte-identical on four fictional charts; with
#121, -24–29% end to end.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01DbBXoz1Qk3y9buDv1mkmTu

scripts/pl9_full_data_export.py

@@ -2472,19 +2472,18 @@ def _append_annual_method_reference(markdown: str, packet: dict, language: str)
     return markdown.rstrip() + "\n\n" + extra + "\n"
 
 
-def read_full_data_domain(packet: Mapping, domain: str) -> dict:
-    """Deep-copied packet view for one consult domain.
+def full_data_domain_base(packet: Mapping) -> dict:
+    """The detached, domain-independent part of every domain view.
 
-    Field selection belongs to the consult card. This entry only freezes the
-    domain name and detaches the copy from the live packet.
+    One deep copy of the packet's shared sections. ``read_full_data_domain``
+    used to make this copy once per domain, and a long report reads five
+    domains twice (facts, then the leaf check): ten copies of the whole
+    ``worksheets`` tree for read-only use (issue #122). Callers that read
+    several domains of one packet build this once and pass it as ``base``.
     """
-    if domain not in FULL_DATA_DOMAINS:
-        raise KeyError(domain)
     if not isinstance(packet, Mapping):
         raise TypeError("packet must be a mapping")
     copied = copy.deepcopy({
-        "domain": domain,
-        "label": FULL_DATA_DOMAINS[domain],
         "report_version": packet.get("report_version"),
         "birth_info": packet.get("birth_info"),
         "core_chart": packet.get("core_chart"),
@@ -2496,3 +2495,19 @@ def read_full_data_domain(packet: Mapping, domain: str) -> dict:
     if isinstance(timing, dict):
         timing.pop("pyjhora_annual_method_reference", None)
     return copied
+
+
+def read_full_data_domain(packet: Mapping, domain: str, *, base: Mapping | None = None) -> dict:
+    """Detached packet view for one consult domain.
+
+    Field selection belongs to the consult card. This entry only freezes the
+    domain name and detaches the view from the live packet. With ``base`` (from
+    ``full_data_domain_base`` of the same packet) the shared sections are that
+    one copy; views of different domains then share it and must be read only.
+    """
+    if domain not in FULL_DATA_DOMAINS:
+        raise KeyError(domain)
+    if not isinstance(packet, Mapping):
+        raise TypeError("packet must be a mapping")
+    shared = full_data_domain_base(packet) if base is None else base
+    return {"domain": domain, "label": FULL_DATA_DOMAINS[domain], **shared}