feat(search): add whoosh-compat, the shared field table and the field registry

src/documents/search/_fields.py

@@ -0,0 +1,42 @@
+from __future__ import annotations
+
+from whoosh_compat import FieldKind
+from whoosh_compat import FieldSpec
+from whoosh_compat import SubpathSpec
+
+# Internal-only schema fields with no query-syntax meaning of their own
+# (sort shadow fields, bigram CJK fields, simple_title/simple_content,
+# autocomplete_word, notes_text) are NOT represented here — they are
+# declared in _schema.py's field_descriptors().
+#
+# analyzer/pattern_normalizer are deliberately left at FieldSpec's default
+# (None): they're language-specific and only meaningful to whoosh-compat's
+# parser, so _registry.py attaches them per-language via dataclasses.replace()
+# rather than PUBLIC_FIELDS declaring them itself. _schema.py only reads
+# name/kind/fast and never sees the analyzer at all.
+PUBLIC_FIELDS: tuple[FieldSpec, ...] = (
+    FieldSpec("title", FieldKind.TEXT),
+    FieldSpec("content", FieldKind.TEXT),
+    FieldSpec("correspondent", FieldKind.TEXT),
+    FieldSpec("document_type", FieldKind.TEXT, aliases=("type",)),
+    FieldSpec("storage_path", FieldKind.TEXT, aliases=("path",)),
+    FieldSpec("original_filename", FieldKind.TEXT),
+    FieldSpec("tag", FieldKind.TEXT, comma_values=True),
+    FieldSpec("checksum", FieldKind.KEYWORD),
+    FieldSpec("asn", FieldKind.U64, fast=True),
+    FieldSpec("page_count", FieldKind.U64, fast=True),
+    FieldSpec("num_notes", FieldKind.U64, fast=True),
+    FieldSpec("created", FieldKind.DATE, date_only=True, fast=True),
+    FieldSpec("modified", FieldKind.DATETIME, fast=True),
+    FieldSpec("added", FieldKind.DATETIME, fast=True),
+    FieldSpec(
+        "notes",
+        FieldKind.JSON,
+        subpaths={"user": SubpathSpec(), "note": SubpathSpec(default=True)},
+    ),
+    FieldSpec(
+        "custom_fields",
+        FieldKind.JSON,
+        subpaths={"name": SubpathSpec(), "value": SubpathSpec(default=True)},
+    ),
+)