Add recall debug panel

[yvette-carlisle]

Summary

• Add elf.recall_debug_panel/v1 service readback across memory traces, source docs, knowledge pages, graph facts, and Dreaming proposals.
• Wire POST /v2/admin/recall-debug/panel and MCP tool elf_recall_debug_panel with server-context-only identity/read_profile handling.
• Add docs, version registry, benchmark evidence snapshot, and eval guard for non-pass boundaries, retained replay candidates, and docs effective cap.

Validation

• cargo make lint-fix
• cargo make check
• cargo test -p elf-mcp recall_debug_panel -- --nocapture
• decodex docs check
• git diff --check

Decodex

• Authority: XY-1022
• Manual takeover was required after Decodex run failed before agent execution.