v1.2.11 — native tools on free models, self-healing routes

Fixed

• Free models can call tools again. The free-tier gate authenticates the client
  through headers alone (User-Agent, x-opencode-client,
  x-opencode-session + x-opencode-session-id); once the duplicate session
  header from 1.2.10 is present it accepts a normal pi request. The body-shaping
  layer (title-generator marker, flattened history, stripped tools) and the
  text-tool protocol that replaced native tools are therefore unnecessary, and
  they were what broke tool calls: big-pickle (zero-cost but without a -free
  suffix) was never converted back into a tool call, mimo-v2.6-flash-free
  emitted several calls inside one fenced block and lost all of them, and
  weaker models invented their own fences. Both are removed; free models now
  send and receive native tools, verified end-to-end (read + bash + follow-up
  turn) on big-pickle, muse-spark-1.3-contributor-free,
  mimo-v2.6-flash-free, nemotron-3-ultra-free and
  nemotron-3.5-lightning-free.
• GATE_UA tracks opencode 2.0.32. The gate also re-checked its content rules:
  free requests now need stream: true and at least one tool definition, and
  the versionless opencode/cli user agent is rejected; pi's own request
  satisfies all of it, so the body still passes through untouched.
• Cached catalogs cannot pin a stale protocol any more: healZenRoute
  re-derives the free-tier route from the model id on every read, in
  getModels()/getAllModels() — the accessors every request path uses.
  A models-store.json written by an older version (which survives upgrades
  because pi's post-login refresh is offline) no longer causes
  400 ModelProtocolUnsupported.

Highlights

• Free models call native tools again — read, bash, multi-turn — with the
  request body passing through untouched.
• A stale models-store.json can no longer pin a model to a dead protocol;
  routing is re-derived from code on every read (no more
  400 ModelProtocolUnsupported after upgrades).
• Gate header User-Agent tracks opencode 2.0.32; probed against the live
  gateway (free requests need stream: true + at least one tool definition,
  both of which pi sends anyway).
• Verified end-to-end on big-pickle, mimo-v2.6-flash-free,
  nemotron-3-ultra-free, nemotron-3.5-lightning-free,
  muse-spark-1.3-contributor-free, and the new beam-free,
  glm-5.3-flash-free, nemotron-3.5-super-vl-free, space-bunny-free,
  deepseek-v4.1-flash-free.

Upgrade: pi install npm:opencode-zen-oauth then restart pi.