feat(provider-umans): Umans AI Coding Plan provider + openai-stream lib

Extract a generic @dispatch/openai-stream library from provider-openai-compat
(convert-messages, convert-tools, parse-sse, listModels, stream, provider),
parameterizing createOpenAICompatProvider with uid=1000(tradam) gid=1000(tradam) groups=1000(tradam),966(docker),968(ollama),998(wheel) +  hook.
Refactor provider-openai-compat to import from the lib (byte-identical behavior).

New @dispatch/provider-umans extension wraps the Umans OpenAI-compatible backend
(https://api.code.umans.ai/v1). Self-contained: reads UMANS_API_KEY from env
directly (no auth-apikey dep). transformBody maps reasoningEffort →
reasoning_effort (capping xhigh/max → high). Dynamic listModels via GET /v1/models.

host-bin: registered provider-umans in CORE_EXTENSIONS + umans credential
(gated on UMANS_API_KEY — the credential is the model-catalog index).

Verified: tsc EXIT 0, 1059 vitest, biome clean (293 files). Boot smoke:
umans models appear in GET /models (7 models live).

1 files changed, 10 insertions, 0 deletions

diff --git a/packages/host-bin/src/main.ts b/packages/host-bin/src/main.ts
index 59ce47d..1928a8a 100644
--- a/packages/host-bin/src/main.ts
+++ b/packages/host-bin/src/main.ts
@@ -22,6 +22,7 @@ import {
 import { extension as lspExt } from "@dispatch/lsp";
 import { extension as messageQueueExt } from "@dispatch/message-queue";
 import { extension as providerOpenaiCompatExt } from "@dispatch/provider-openai-compat";
+import { extension as providerUmansExt } from "@dispatch/provider-umans";
 import { extension as sessionOrchestratorExt } from "@dispatch/session-orchestrator";
 import { extension as skillsExt } from "@dispatch/skills";
 import { createSqliteStorage, extension as storageSqliteExt } from "@dispatch/storage-sqlite";
@@ -69,6 +70,7 @@ const CORE_EXTENSIONS: readonly Extension[] = [
 	conversationStoreExt,
 	authApikeyExt,
 	providerOpenaiCompatExt,
+	providerUmansExt,
 	toolEditFileExt,
 	toolReadFileExt,
 	toolShellExt,
@@ -148,6 +150,14 @@ async function boot(): Promise<void> {
 	// Assemble the credential list. MVP keeps the hardcoded `opencode` credential
 	// and adds a `claude` credential when an external Anthropic provider is loaded.
 	const credentials = [{ name: "opencode", providerId: "openai-compat" }];
+
+	// The umans credential is always listed (it's the model-catalog index); the
+	// provider itself only registers when UMANS_API_KEY is set, so listCatalog
+	// gracefully skips it when the provider is absent.
+	if (process.env.UMANS_API_KEY) {
+		credentials.push({ name: "umans", providerId: "umans" });
+		logger.info(`Registered credential "umans" → umans provider`);
+	}
 	const hasAnthropic = externalExtensions.some((e) =>
 		e.manifest.contributes?.providers?.includes("anthropic"),
 	);