* fix: drop extra='allow' on FolderForm and FolderUpdateForm
These request models were configured to accept arbitrary extra fields,
which were then merged into the folder row via form_data.model_dump().
In insert_new_folder the server-assigned user_id is placed before the
form spread, so a client-supplied user_id in the request body would
override it and the folder would be persisted against another account.
Strictly typed inputs are the correct shape for these endpoints — the
client has no legitimate reason to send fields beyond the declared
ones, and dropping extra='allow' closes the mass-assignment sink at
the validation layer instead of relying on every callsite to merge
fields in the right order.
* fix: reject unknown fields on FolderForm and FolderUpdateForm
Address review feedback: dropping extra='allow' fell back to Pydantic
v2's default extra='ignore', which only silently drops unknown fields
instead of rejecting them. The intent for these request models is a
strict input contract — fail fast when a client sends anything the
server does not expect — so explicitly set extra='forbid'. This also
makes the hardening visible in the form definition rather than implicit
in the default.
These four Redis calls were the only places in the backend still using
bare cache keys. Every other call already namespaces through
REDIS_KEY_PREFIX, which is how multiple Open WebUI instances sharing a
Redis database stay isolated. Two instances with different
TOOL_SERVER_CONNECTIONS or TERMINAL_SERVER_CONNECTIONS would otherwise
clobber each other's cached OpenAPI specs.
