Run a turn without a host

[eastriverlee]

The README called bluecollar headless and embeddable, but the only way to
see it run was to embed it — so the claim could not be checked without
writing a host first.

What is here

cmd/bluecollar runs one turn against any OpenAI-compatible endpoint and
prints the event ledger to stderr.

model/openaicompatible is the provider behind it, and the first
implementation of the provider port shipped in this module. It is net/http
and encoding/json, so go.mod still requires exactly one library.

ollama serve &
go run ./cmd/bluecollar --model qwen3:4b "In one sentence, what is a POSIX user?"

Evidence

Verified end to end against Ollama qwen3:4b:

task.created  In one sentence, what is a POSIX user?
task.running  assistant
agent.instructions_loaded  {"activeGoal":{"outcomeContract":{"artifactRequirement":"none"…
agent.step_working_set  {"step":1}
agent.tool_palette.built  {"step":1}
llm.call  {"kind":"structured","schemaName":"bluecollar_agent_turn_action","model":"qwen3:4b"…
agent.action  {"action":"finish"…
task.completed
agent.intake  {"classification":"quick_reply","taskShape":"immediate_reply","level":"low"…
agent.goal.completed  {"goalID":"b2886966…"}

go build ./..., go vet ./..., go test ./... pass.

What it deliberately does not do

The runner has no tools. Giving it any would make this a coding agent,
which is the thing the positioning says it is not; a host supplies the tool
set. What it demonstrates is the loop: intake classification, the outcome
contract, the structured action schema, the completion gate — each one a
ledger entry.

README corrections

Two statements had gone stale and one was never right:

• "There is no provider implementation in this module" — there is one now.
• "the only way to drive the loop is to embed it in a host" — no longer true.
• "A terminal front end of its own. Planned on termcn" — termcn is
  TypeScript/React+Ink, so a Go module cannot build on it, and no front end is
  planned here. The interface belongs to whichever host embeds the loop. The
  bullet now says that.

Also trimmed two negative-parallel constructions to get the README from one
per 180 words to one per 300 (AGENTS.md budgets one per 500).