feat: honor --source/--tag in he talk and ka.chat

[Frankie-Xu]

Summary

• Forward keyword-only source_ids / tags from AutoGraph.chat and AutoHypergraph.chat to search_nodes / search_edges.
• base.chat accepts the same kwargs and only passes a name if inspect.signature(type(self).search) contains it.
• he talk gains repeatable --source / --tag with the search inspect-guard against type(ka).chat (“scoped chat” / “no source ledger”). chat_loop keeps the same scope on every turn.
• Document Scoped chat in talk.md and ka.chat(..., source_ids=..., tags=...) in search-and-chat.md (EN + ZH).

Closes yifanfeng97#160

Out of scope

• MCP ask / search scope parameters
• Changing search() semantics or the ledger
• Fake filtering on types without a ledger
• OntoSight chat_callback

Test plan

• uv run pytest tests/cli/test_talk.py tests/types/test_graph_chat_scope.py tests/types/test_document.py tests/types/test_set_provenance.py -q
• ruff check hyperextract and ruff format --check hyperextract

  

[Frankie-Xu]

Opened on the fork by mistake. Review is at yifanfeng97#161 — closing this.