feat(learn): a Viewer opens a shared studyset's material read-only

Every route of a studyset says what the person may do there
(StudysetAccess, set in _inStudyset): whether it is shared with people,
and whether they only view and study it (Halkyon's ADR 0044, D35, D36).

A Viewer opens cards and notes on the same screens, read-only: the rich
fields show their content (LearnContentEditor shows LearnContentView),
the composer's plain fields are read-only and its changes go nowhere,
the note screen reads as a conflict leaves it, each with the line that
the studyset is theirs to view and study. The lists, the card browser
and a study session offer them nothing that writes: no new card, import,
edit, move, rename, reading deadline, reorder or delete. Their tags,
progress and reading stay theirs to change, being their own rows.

Burying and reporting a card are written on its row, which every member
shares, so they are hidden in shared studysets for everyone until they
become each person's own rows (D36).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Signed-off-by: Tizian 「ティツィアーン」 <raisondetredev@pm.me>

docs/adr/0044-shared-spaces-and-collaboration.md

@@ -189,6 +189,15 @@ member reads everything in the space.
   recommendation): the first seal bringing a key ID the space never had, in the same
   transaction. Members the rolling device missed (keys changed, not trusted anew) get
   it later as newcomers do; waiting for every member would roll again and again.
+- **D35.** **A Viewer opens cards, notes and steps read-only** (decided 11 Nov 2026, the
+  agent's recommendation, reading D30): the same screens as an Editor's, their content
+  shown but not editable, without Save, saying the studyset is theirs to view and
+  study; the lists' menus offer them nothing that writes.
+- **D36.** **Burying and reporting a card are hidden in shared studysets for now**
+  (decided 11 Nov 2026, the agent's recommendation): both are written on the card's
+  row, so one member's would be everyone's, and a Viewer's would be refused. They return
+  once they are each person's own rows by the card's ID, as reviews are (D26), a change
+  of the synced tables shipped with a release.
 
 ## Steps
 
@@ -209,8 +218,8 @@ member reads everything in the space.
    @handle, the members, their roles, leaving), each member's own reviews.
    Built 11 Nov 2026 (D27 to D34): the copy into a space of its own, the Share sheet
    with its members, roles, leaving and safety codes, a Viewer's screens read-only,
-   and the key rolled once a member goes. Left: a Viewer's per-item buttons inside the
-   material tabs, and a message for a write the engine refuses them.
+   the key rolled once a member goes, and a Viewer's material opened read-only (D35),
+   burying and reporting hidden in shared studysets (D36).
 5. **Invitations by email and by link** (D4, D5), the Inbox.
 6. **Agents** (D6, D7, D10, D12).