Switch from Bifrost to LiteLLM; add Matrix channel; update rules

Infrastructure:
- docker-compose.yml: replace bifrost container with LiteLLM proxy
  (host.docker.internal:4000); complex model → deepseek-r1:free via
  OpenRouter; add Matrix URL env var; mount logs volume
- bifrost-config.json: add auth_config + postgres config_store (archived)

Routing:
- router.py: full semantic 3-tier classifier rewrite — nomic-embed-text
  centroids for light/medium/complex; regex pre-classifiers for all tiers;
  Russian utterance sets expanded
- agent.py: wire LiteLLM URL; add dry_run support; add Matrix channel

Channels:
- channels.py: add Matrix adapter (_matrix_send via mx- session prefix)

Rules / docs:
- agent-pipeline.md: remove /think prefix requirement; document automatic
  complex tier classification
- llm-inference.md: update BIFROST_URL → LITELLM_URL references; add
  remote model note for complex tier
- ARCHITECTURE.md: deleted (superseded by README.md)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/rules/agent-pipeline.md

@@ -1,9 +1,11 @@
 # Agent Pipeline Rules
 
 ## Tiers
-- Complex tier requires `/think ` prefix. Any LLM classification of "complex" is downgraded to medium. Do not change this.
-- Medium is the default tier. Light is only for trivial static-knowledge queries matched by regex or LLM.
+- Routing is fully automatic: router classifies into light/medium/complex via 3-way embedding similarity.
+- Complex tier is reached automatically for deep research queries — no prefix required.
+- Medium is the default tier. Light is only for trivial static-knowledge queries matched by regex or embedding.
 - Light tier upgrade to medium is automatic when URL content is pre-fetched or a fast tool matches.
+- `tier_override` API parameter still allows callers to force a specific tier (e.g. `adolf-deep` model → complex).
 
 ## Medium agent
 - `_DirectModel` makes a single `ainvoke()` call with no tool schema. Do not add tools to the medium agent.