feat: Generate REC/2023/03 liquid chromatography tabular schema models (#1188)

## Summary
- Adds support for flat tabular schemas (root `properties` without
`allOf`) in the codegen pipeline
- Generates the LC REC/2023/03 model, which uses this older flat format
— previously produced empty output
- Stabilizes unit dedup ordering in `units.py` and `quantity_values.py`
so adding older schema dependencies doesn't change existing unit strings

## Changes
- **`generator.py`**: Broaden `_is_adm_schema` to detect flat schemas
with nested object properties; merge root-level properties in
`_generate_adm_module` before `allOf` processing
- **`generate.py`**: Add secondary sort key for deterministic unit class
name assignment; read existing `quantity_values.py` to preserve
committed unit strings when older schemas introduce alternate spellings
- **New files**: Cached JSON schemas (core REC/2021/12, core
REC/2022/12, qudt REC/2021/12, qudt REC/2023/03, LC REC/2023/03) and
generated models

## Test plan
- [x] `hatch run test_all.py3.10:pytest tests/ -x -q` — all 1112 tests
pass
- [x] `hatch run lint` — clean (ruff, black, mypy)
- [x] `hatch run scripts:generate-schemas --all` produces no changes to
existing committed models
- [x] `test_generated_models_are_up_to_date` passes (regeneration in tmp
dir matches committed)
- [x] `test_single_technique_smoke` passes for all cached schemas

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: nathan-stender

src/allotropy/allotrope/models/adm/core/rec/_2021/_12/core.py

@@ -0,0 +1,269 @@
+# generated by allotropy.schema_gen
+# Re-exports imported types so downstream modules can import from here.
+# ruff: noqa: F401
+
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from typing import Any
+
+from allotropy.allotrope.models.shared.definitions.definitions import (
+    TClass,
+    TQuantityValue,
+    TUnit,
+)
+
+
+@dataclass(frozen=True, kw_only=True)
+class Asm:
+    pass
+
+
+@dataclass(frozen=True, kw_only=True)
+class MixedItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+
+
+@dataclass(frozen=True, kw_only=True)
+class OrderedItem:
+    field_index: int | None = field(default=None, metadata={"json_name": "@index"})
+
+
+TArray = list[Any]
+
+
+@dataclass(frozen=True, kw_only=True)
+class TBooleanValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: bool
+
+
+@dataclass(frozen=True, kw_only=True)
+class TByteValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: int
+
+
+@dataclass(frozen=True, kw_only=True)
+class TDateTimeStampValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: str
+
+
+@dataclass(frozen=True, kw_only=True)
+class TDateTimeValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: str
+
+
+@dataclass(frozen=True, kw_only=True)
+class TDateValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: str
+
+
+@dataclass(frozen=True, kw_only=True)
+class TDecimalValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: float
+
+
+@dataclass(frozen=True, kw_only=True)
+class TDoubleValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: float
+
+
+@dataclass(frozen=True, kw_only=True)
+class TDurationValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: str
+
+
+@dataclass(frozen=True, kw_only=True)
+class TFloatValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: float
+
+
+@dataclass(frozen=True, kw_only=True)
+class TIRIValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: str
+
+
+@dataclass(frozen=True, kw_only=True)
+class TIntValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: int
+
+
+@dataclass(frozen=True, kw_only=True)
+class TIntegerValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: int
+
+
+@dataclass(frozen=True, kw_only=True)
+class TLongValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: int
+
+
+TNamed = str
+
+
+@dataclass(frozen=True, kw_only=True)
+class TObject:
+    pass
+
+
+TReference = str
+
+
+TResource = str
+
+
+@dataclass(frozen=True, kw_only=True)
+class TShortValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: int
+
+
+@dataclass(frozen=True, kw_only=True)
+class TStringValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: str
+
+
+@dataclass(frozen=True, kw_only=True)
+class TTimeValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: str
+
+
+@dataclass(frozen=True, kw_only=True)
+class TUnsignedByteValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: int
+
+
+@dataclass(frozen=True, kw_only=True)
+class TUnsignedIntValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: int
+
+
+@dataclass(frozen=True, kw_only=True)
+class TUnsignedLongValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: int
+
+
+@dataclass(frozen=True, kw_only=True)
+class TUnsignedShortValueItem:
+    field_type: TClass = field(metadata={"json_name": "@type"})
+    value: int
+
+
+TBooleanValue = TBooleanValueItem | bool
+
+
+TByteValue = TByteValueItem | int
+
+
+TDateTimeStampValue = TDateTimeStampValueItem | str
+
+
+TDateTimeValue = TDateTimeValueItem | str
+
+
+TDateValue = TDateValueItem | str
+
+
+TDecimalValue = TDecimalValueItem | float
+
+
+TDoubleValue = TDoubleValueItem | float
+
+
+TDurationValue = TDurationValueItem | str
+
+
+TFloatValue = TFloatValueItem | float
+
+
+TIRIValue = TIRIValueItem | str
+
+
+TIntValue = TIntValueItem | int
+
+
+TIntegerValue = TIntegerValueItem | int
+
+
+TLongValue = TLongValueItem | int
+
+
+TShortValue = TShortValueItem | int
+
+
+TStringValue = TStringValueItem | str
+
+
+TTimeValue = TTimeValueItem | str
+
+
+TUnsignedByteValue = TUnsignedByteValueItem | int
+
+
+TUnsignedIntValue = TUnsignedIntValueItem | int
+
+
+TUnsignedLongValue = TUnsignedLongValueItem | int
+
+
+TUnsignedShortValue = TUnsignedShortValueItem | int
+
+
+TNumericValue = (
+    TByteValue
+    | TDecimalValue
+    | TDoubleValue
+    | TFloatValue
+    | TIntValue
+    | TIntegerValue
+    | TLongValue
+    | TShortValue
+    | TUnsignedByteValue
+    | TUnsignedIntValue
+    | TUnsignedLongValue
+    | TUnsignedShortValue
+)
+
+
+TOrderedValue = (
+    TDateTimeStampValue
+    | TDateTimeValue
+    | TDateValue
+    | TNumericValue
+    | TStringValue
+    | TTimeValue
+)
+
+
+@dataclass(frozen=True, kw_only=True)
+class TRangeValue:
+    min_inclusive: TOrderedValue | None = field(
+        default=None, metadata={"json_name": "minInclusive"}
+    )
+    min_exclusive: TOrderedValue | None = field(
+        default=None, metadata={"json_name": "minExclusive"}
+    )
+    max_inclusive: TOrderedValue | None = field(
+        default=None, metadata={"json_name": "maxInclusive"}
+    )
+    max_exclusive: TOrderedValue | None = field(
+        default=None, metadata={"json_name": "maxExclusive"}
+    )
+    unit: TUnit | None = None