diff --git a/phono-models/migrations/20260120062457_fix_email_unique_constraint.down.sql b/phono-models/migrations/20260120062457_fix_email_unique_constraint.down.sql
new file mode 100644
index 0000000..f898462
--- /dev/null
+++ b/phono-models/migrations/20260120062457_fix_email_unique_constraint.down.sql
@@ -0,0 +1,2 @@
+drop index if exists users_email_idx;
+create index on users (email);
diff --git a/phono-models/migrations/20260120062457_fix_email_unique_constraint.up.sql b/phono-models/migrations/20260120062457_fix_email_unique_constraint.up.sql
new file mode 100644
index 0000000..90a4112
--- /dev/null
+++ b/phono-models/migrations/20260120062457_fix_email_unique_constraint.up.sql
@@ -0,0 +1,2 @@
+drop index if exists users_email_idx;
+create unique index on users (email);
diff --git a/phono-models/src/user.rs b/phono-models/src/user.rs
index eae9521..07c0196 100644
--- a/phono-models/src/user.rs
+++ b/phono-models/src/user.rs
@@ -110,29 +110,55 @@ returning id, uid, email
             .await?
             {
                 user
-            } else if uid.is_some() {
-                // Conflict should have been on at least `uid`, meaning that the
-                // user already exists and its fields are fully populated.
-                query_as!(User, "select id, uid, email from users where uid = $1", uid)
-                    .fetch_one(app_db.get_conn())
-                    .await?
             } else {
-                // Conflict must have been on `email`, meaning that the user
-                // already exists, though its `uid` may not be up to date. Use
-                // `COALESCE()` on the `uid` value to ensure that it is not
-                // inadvertently removed if present.
-                query_as!(
+                // Conflict may have been on either or both of `email` and
+                // `uid`.
+                //
+                // If the conflict was on `email`, we want to ensure that `uid`
+                // is updated if and only if it is currently null. This can be
+                // accomplished using `COALESCE()` with the current `uid` value
+                // as the first argument. The parameterized value will only be
+                // used if the current value is null.
+                //
+                // If the conflict was on `uid`, we merely want to return the
+                // record with the matching `uid`.
+                //
+                // If both fields conflicted then the `UPDATE` query will be
+                // sufficient, but if the operation is using a different email
+                // address than the one already stored then we will need one
+                // final `SELECT` query to guarantee that we obtain a result.
+                // Assuming that the caller queries by `uid` prior to starting
+                // the upsert, this last query should only be hit when two HTTP
+                // requests are running the auth flow concurrently.
+                if let Some(user) = query_as!(
                     User,
                     "
 update users
-set uid = coalesce($1, uid)
-where email = lower($1)
+set uid = coalesce(uid, $1)
+where email = lower($2)
 returning id, uid, email
 ",
+                    uid,
                     email,
                 )
-                .fetch_one(app_db.get_conn())
+                .fetch_optional(app_db.get_conn())
                 .await?
+                {
+                    user
+                } else {
+                    User::with_uid(
+                        // TODO: This should hold true *unless* the database is
+                        // "tampered with" by an outside actor (such as a
+                        // developer performing manual maintenance). While such
+                        // an edge case is beyond the scope of the server's
+                        // responsibilities, panicking may be considered an
+                        // overreaction.
+                        uid.expect("uid must be non-null to cause a database conflict"),
+                    )
+                    .fetch_optional(app_db)
+                    .await?
+                    .ok_or(sqlx::Error::RowNotFound)?
+                }
             },
         )
     }
diff --git a/phono-server/src/routes/workspaces_single/grant_workspace_privilege_handler.rs b/phono-server/src/routes/workspaces_single/grant_workspace_privilege_handler.rs
index ac90aef..6134434 100644
--- a/phono-server/src/routes/workspaces_single/grant_workspace_privilege_handler.rs
+++ b/phono-server/src/routes/workspaces_single/grant_workspace_privilege_handler.rs
@@ -7,6 +7,7 @@ use phono_backends::{escape_identifier, pg_database::PgDatabase, rolnames::ROLE_
 use phono_models::{
     accessors::{Accessor as _, Actor, workspace::WorkspaceAccessor},
     user::User,
+    workspace_user_perm::WorkspaceMembership,
 };
 use serde::Deserialize;
 use sqlx::query;
@@ -84,7 +85,7 @@ pub(super) async fn post(
         .await?
         .datname;
     query(&format!(
-        "grant connect on database {db_name_esc} to {rolname}",
+        "grant connect on database {db_name_esc} to {rolname} with grant option",
         db_name_esc = escape_identifier(&db_name),
         rolname = escape_identifier(&format!(
             "{ROLE_PREFIX_USER}{user_id}",
@@ -93,6 +94,20 @@ pub(super) async fn post(
     ))
     .execute(root_client.get_conn())
     .await?;
+    query(&format!(
+        "grant usage, create on schema phono to {rolname} with grant option",
+        rolname = escape_identifier(&format!(
+            "{ROLE_PREFIX_USER}{user_id}",
+            user_id = target_user.id.simple()
+        ))
+    ))
+    .execute(root_client.get_conn())
+    .await?;
+    WorkspaceMembership::upsert()
+        .workspace_id(workspace_id)
+        .user_id(target_user.id)
+        .execute(&mut app_db)
+        .await?;
 
     Ok(navigator
         .workspace_page()
diff --git a/phono-server/templates/workspaces_multi/list.html b/phono-server/templates/workspaces_multi/list.html
index 879138a..bfb3a8d 100644
--- a/phono-server/templates/workspaces_multi/list.html
+++ b/phono-server/templates/workspaces_multi/list.html
@@ -33,10 +33,5 @@
       {% endfor %}
     </menu>
   </section>
-  <section class="workspace-nav__section">
-    <div class="workspace-nav__heading">
-      <h1>Shared With Me</h1>
-    </div>
-  </section>
 </nav>
 {% endblock %}