config: route all presets through hossenfelder per issue #12

Resolves issue #12 by partial-accept of the recommendation.

What landed:
  - Single broker URL: http://hossenfelder.fritz.box:8082 for all three
    presets (fast / deep / cloud). Server-side model-aware routing; no
    client-side cloud auth (proxy holds the OpenRouter bearer).
  - Models from hossenfelder's /v1/models inventory:
      fast  -> qwen2.5-coder-1.5b-q4_k_m.gguf  (boltzmann local)
      deep  -> mistral-nemo-12b-instruct        (boltzmann local)
      cloud -> anthropic/claude-haiku-4.5       (OpenRouter route)
  - `cloud` was already pointing at hossenfelder but with https://; flipped
    to http:// so it matches the proxy's actual scheme.

What deferred:
  - Schema rename `models` -> `brokers` (and the 5-cloud-preset shape
    suggested in #12) — would touch repl.lua + broker.lua. Not blocking
    Phase 7. If multi-preset becomes useful in practice, file a separate
    issue for the rename then.

Phase 7 verification (live broker test):
  - broker.chat(fast, [user="say pong"]) -> "CMD: echo pong" in ~3s
  - multi-turn arithmetic (7*8=56, *2=112) preserved across turns

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

config.lua

@@ -1,26 +1,31 @@
 -- config.lua — model registry, routing rules, user preferences.
 -- Loaded with dofile() at startup; returns a plain Lua table.
 -- See docs/PHASE0.md §10 for resolution order and full schema.
+--
+-- Per issue #12: hossenfelder is the canonical single-URL broker. It does
+-- model-aware routing server-side (local models on boltzmann; cloud routes
+-- through OpenRouter using its own bearer auth — no client-side key here).
+-- Discovery: GET http://hossenfelder.fritz.box:8082/v1/models.
+
+local HOSSENFELDER = "http://hossenfelder.fritz.box:8082"
 
 return {
     default_model = "fast",
 
     models = {
         fast = {
-            endpoint    = "http://dirac.fritz.box:8081",
+            endpoint    = HOSSENFELDER,
-            model       = "qwen-coder-7b-snappy-8k",
+            model       = "qwen2.5-coder-1.5b-q4_k_m.gguf",
             temperature = 0.2,
         },
         deep = {
-            endpoint    = "http://dirac.fritz.box:8080",
+            endpoint    = HOSSENFELDER,
-            model       = "qwen-coder-7b-32k",
+            model       = "mistral-nemo-12b-instruct",
             temperature = 0.1,
         },
         cloud = {
-            endpoint    = "https://hossenfelder.fritz.box:8082",
+            endpoint    = HOSSENFELDER,
             model       = "anthropic/claude-haiku-4.5",
-            -- Hossenfelder forwards to OpenRouter using its own key from
-            -- /etc/conf.d/llm-proxy on the LXC; no client-side key needed.
             temperature = 0.2,
         },
     },