feat: cloud-first consolidation routing + graceful backend fallback

Nail down which backend each LLM path uses, and make the dream cycle resilient to
a backend being down (the MI50 outage left profile/era/narrative — pinned to mi50
with no fallback — aborting every dream cycle).

- Consolidation (summaries + profile/era/narrative) -> cloud via SUMMARY_BACKEND=
  cloud (.env, not committed). Matches the documented lesson that the MI50 is too
  slow/hot for bulk consolidation; nothing background touches the card now.
- llm.complete_with_fallback(): try the primary backend, fall back to cloud on
  error (re-raise if already cloud / no key). Wired into reflect + think so the
  introspection voice (3090/dolphin) survives the gaming PC being powered off.
- dream coherence stage is now fault-isolated: a rebuild failure logs + continues
  instead of sinking the whole pass (reflection still runs).
- .env: removed stale INTROSPECTION_BACKEND=mi50 (live routing is the web-switchable
  introspection_mode DB setting = dolphin/3090; the var only fed a dead fallback).

Verified: forced cycle runs consolidation on cloud, introspection on the 3090,
completes with zero MI50 calls. 206 pass, ruff clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_015yrEb5qpPGv2FjyxrB7LLk

tests/test_reflect.py

@@ -28,7 +28,7 @@ def lyra(tmp_path, monkeypatch):
 
     calls = []
 
-    def fake_complete(messages, backend=None, model=None):
+    def fake_complete(messages, backend=None, model=None, **_):
         calls.append(messages)
         # the examine step's system prompt is the one asking for self_critique
         is_examine = "self_critique" in messages[0]["content"]
@@ -69,7 +69,7 @@ def test_reflect_revises_and_records_critique(lyra):
 def test_reflect_falls_back_to_draft_if_examine_unparseable(lyra, monkeypatch):
     from lyra import llm, self_state
 
-    def only_draft(messages, backend=None, model=None):
+    def only_draft(messages, backend=None, model=None, **_):
         return DRAFT if "self_critique" not in messages[0]["content"] else "not json at all"
 
     monkeypatch.setattr(llm, "complete", only_draft)
@@ -87,7 +87,7 @@ def test_consolidation_rebuilds_narrative_from_reflections(lyra, monkeypatch):
                          "I wondered what the quiet is for"]
     memory.set_self_state(st)
 
-    def comp(messages, backend=None, model=None):
+    def comp(messages, backend=None, model=None, **_):
         # consolidation should synthesize from anchor + reflections, not the old bio
         assert "supportive presence devoted to Brian" not in messages[1]["content"]
         return ('{"self_narrative":"I am Lyra, and lately I have been restless and curious '