Resolve Feishu @_user_N / @_all placeholders into display names plus a
structured [Mentioned: Name (open_id=...), ...] hint so agents can both
reason about who was mentioned and call Feishu OpenAPI tools with stable
open_ids. Strip bot self-mentions only at message edges (leading
unconditionally, trailing only before whitespace/terminal punctuation)
so commands parse cleanly while mid-text references are preserved.
Covers both plain-text and rich-post payloads.
Also fixes a pre-existing hydration bug: Client.request no longer accepts
the 'method' kwarg on lark-oapi 1.5.3, so bot identity silently failed
to hydrate and self-filtering never worked. Migrate to the
BaseRequest.builder() pattern and accept the 'app_name' field the API
actually returns. Tighten identity matching precedence so open_id is
authoritative when present on both sides.
e86acad8f1