feat: split introspection backend from consolidation (trial Dolphin for her voice)

reflect()/think() can now run on a different model than memory consolidation:
INTROSPECTION_BACKEND / INTROSPECTION_MODEL (default to SUMMARY_BACKEND, so unset =
unchanged). Consolidation (summaries/profile/narrative) keeps the capable model;
her *voice* (reflections, thoughts) can run a steerable tune. dream.py lets
reflect()/think() self-resolve to the introspection backend; both now thread a
`model` override into llm.complete.

Trial live: introspection -> dolphin3:8b on the 3090; consolidation -> Qwen-32B
on the MI50. Suite 73 green, ruff clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

.env.example

@@ -40,3 +40,8 @@ LYRA_TIMEZONE=America/New_York
 # --- External input feeds (RSS/Atom, comma-separated) ---
 LYRA_FEEDS=https://hnrss.org/frontpage,https://www.pokernews.com/rss.php
 FEED_REACT_PROB=0.5      # chance a new thought reacts to a feed item
+
+# --- Introspection backend (reflect/think) — her *voice*, may differ from consolidation ---
+# Defaults to SUMMARY_BACKEND. Set to run her reflections/thoughts on a steerable model.
+INTROSPECTION_BACKEND=
+INTROSPECTION_MODEL=