chore(deps): re-lock with CI's uv, restore two unrelated downgrades

The lock carried ~490 redundant `sys_platform == 'darwin' or sys_platform
== 'linux'` markers and had quietly pinned sqlparse to 0.5.5 and
pymdown-extensions to 11.0, both older than dev and neither related to
search. Re-resolving with uv 0.12.x (CI's pinned series) drops the markers
and restores both to dev's versions, taking the lock's diff against dev
from 1428 lines to 51. The only version line that now differs from dev is
whoosh-compat's own.

Three versions move here, not two: whoosh-compat also goes 0.1.0.dev0 ->
0.1.0, picked up from the sibling repo's own bump through the local path
dependency rather than from anything this re-lock decided.

A plain `uv lock` is a no-op here, since the lock is already
self-consistent; the markers are only recomputed when the resolution
actually re-runs.

Also drops a TODO's pointer to a spec file deleted in e50421542, and
corrects a comment claiming custom fields have a companion text field for
full-text search. They do not: no such field is ever written, and their
values are reachable only through the JSON field. Records that notes_text
is absent from _DEFAULT_SEARCH_FIELDS, so it is highlight-only by design.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

pyproject.toml

@@ -169,10 +169,8 @@ psycopg-c = [
 torch = [
   { index = "pytorch-cpu" },
 ]
-# TODO: switch to a pinned PyPI version once whoosh-compat releases
-# (expected around this repo's PR 3 in the transition plan); fall back to a
-# pinned git commit SHA if that release slips. See
-# docs/superpowers/specs/2026-08-07-whoosh-compat-transition-design.md.
+# TODO: switch to a pinned PyPI version once whoosh-compat releases; fall back
+# to a pinned git commit SHA if that release slips.
 whoosh-compat = { path = "../whoosh-compat" }
 
 [tool.ruff]

src/documents/search/_backend.py

@@ -528,7 +528,9 @@ class TantivyBackend:
 
         # Notes — JSON for structured queries (notes.user:alice, notes.note:text).
         # notes_text is a plain-text companion for snippet/highlight generation;
-        # tantivy's SnippetGenerator does not support JSON fields.
+        # tantivy's SnippetGenerator does not support JSON fields. It is not in
+        # _DEFAULT_SEARCH_FIELDS, so an unqualified query never searches it: a
+        # note matches through the JSON field or not at all.
         num_notes = 0
         note_texts: list[str] = []
         for note in document.notes.all():
@@ -544,8 +546,9 @@ class TantivyBackend:
         if note_texts:
             doc.add_text("notes_text", " ".join(note_texts))
 
-        # Custom fields — JSON for structured queries (custom_fields.name:x, custom_fields.value:y),
-        # companion text field for default full-text search.
+        # Custom fields — JSON for structured queries (custom_fields.name:x,
+        # custom_fields.value:y). There is no companion text field here, unlike
+        # notes: custom field values are reachable only through the JSON field.
         for cfi in document.custom_fields.all():
             search_value = cfi.value_for_search
             # Skip fields where there is no value yet