feat(adapters): SME adapter for the Go MemPalace server (#255)

Add MemPalaceServerAdapter for sefodo26's Go reimplementation of the
MemPalace server (fork: techempower-org/mempalace-server). Talks to the
server's REST API (/mp/api/v1, bearer auth) — the same shape the Go
project's own benchmark harness uses — so SME numbers stay comparable.

- ingest_corpus: one drawer per row (content ← document|content|text;
  wing/room ← row|metadata|session_id|id fallbacks), optional
  wing-scoped reset-before-ingest for per-question-haystack isolation.
  Handles the server's deterministic-id idempotency (already_exists) and
  bullet-splitting (bullets_stored) responses. Never raises on transport
  failure — errors are captured into the result dict.
- query: POST /search, constructor n_results default, optional
  wing/room/max_distance (omitted by default → server default, matching
  the reference benchmark). Returns a QueryResult with error set, never
  raises.
- get_graph_snapshot: projects GET /taxonomy through the shared
  project_graph (wing/room/member_of), identical to the daemon adapter.
- reset(wing=None): paginated list+delete isolation (the server has no
  per-request tenant; MEMPALACE_TENANT_ID is server-level config).
- get_harness_manifest: real Cat 9b surfaces — the MCP endpoint (health
  probe) and REST search — since the server's core identity is an MCP
  server. get_flat_retrieval / get_ontology_source provided.
- Config via constructor → env (MEMPALACE_SERVER_URL / _API_KEY /
  _TENANT) → docker-compose defaults; zero-config against a fresh
  `docker compose up`.

Registered in sme.cli (aliases mempalace-server / mempalace_server /
mp-server; no rename). Added to the fork contract test kit. 31 mocked
unit tests (fake_urlopen_factory) + 1 opt-in live round-trip test
(MEMPALACE_SERVER_LIVE=1, skips cleanly when absent). ruff check clean;
full suite green (pre-existing hindsight network failures unrelated).

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

Author: jphein