research: Trilium (TriliumNext) deep dive (note cloning/DAG hierarchy, attribute inheritance, HTML-native); UC-66/67

SQLite-local PKB whose standout is note cloning — a single note can sit in
multiple tree locations at once via the note (identity) vs branch
(placement) split, so the hierarchy is a DAG, not a tree, with no single
canonical path. The identity-not-equal-placement model is the clean way to
represent a page in multiple locations/shards and the namespace-level form
of the clone/reference primitive. Also: attributes (labels + typed
relations) are inherited + templated, so metadata is computed (own +
inherited + template), not a flat bag; content opacity is per-item
(per-note encryption / protected notes), refining the proposed 12th
spectrum; HTML-native (CKEditor, lossy to Markdown); dual extension
surface (scripting code notes + ETAPI token REST). TriliumNext is the
active community fork of zadam's Trilium (TWiki->Foswiki pattern). Added
UC-66 (DAG hierarchy / note cloning), UC-67 (inherited/templated
attributes, effective vs own); enriched UC-15/22/34/38/42/61. Catalog now
67 UCs. Architecture for SHARD-WP-0002 T11/T12/T14/T15/T16: DAG namespace
+ identity/placement split, computed/inherited metadata, per-item content
opacity, HTML source model, scripting + ETAPI host surfaces.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

SCOPE.md

@@ -19,9 +19,9 @@ Learnings update both SCOPE and INTENT where necessary.
 |-------|-------|
 | Code | Python package scaffold (`src/shard_wiki/`, smoke tests only) |
 | Intent | `INTENT.md` established; authorization-in-core amendments drafted |
-| Research | yawex prior art; c2 origins; federation concepts; wikiengines overview (`research/260608-*/`); XWiki/TWiki/Foswiki deep dives (`research/260613-*/`); Xanadu + ZigZag + Roam + Obsidian + Notion + Joplin + Logseq + local-first workspaces (Anytype/AFFiNE/AppFlowy) deep dives & shard-spectrum synthesis (`research/260614-*/`) |
+| Research | yawex prior art; c2 origins; federation concepts; wikiengines overview (`research/260608-*/`); XWiki/TWiki/Foswiki deep dives (`research/260613-*/`); Xanadu + ZigZag + Roam + Obsidian + Notion + Joplin + Logseq + local-first workspaces (Anytype/AFFiNE/AppFlowy) + Trilium deep dives & shard-spectrum synthesis (`research/260614-*/`) |
 | Demand | NetKingdom integration asks captured, not yet negotiated |
-| Spec | Architecture blueprint drafted; UseCaseCatalog 65 UCs from research; PRD/TSD scaffolds |
+| Spec | Architecture blueprint drafted; UseCaseCatalog 67 UCs from research; PRD/TSD scaffolds |
 | Work | `SHARD-WP-0001` active (6 tasks); `SHARD-WP-0002` active (16 tasks: T1–T10 federation + T11–T16 adapter contract) |
 
 ## In Scope (today)