Remove the direct Anthropic subscription flow

Todo2026-10-28jp

domain: llmllm-provider: anthropicpackage: jp_cli, jp_config, jp_llmtype: task

KindChore

providers.llm.anthropic.subscription_flow = "direct" sends JP-stored Claude Pro/Max OAuth tokens straight to the Messages API. Anthropic does not sanction that use, and RFD 110 already made the Claude Code (ACP) route the default. Remove the direct flow. Anyone who still wants it can ship it as an unofficial plugin once providers are pluggable.

Scope

• jp_config: the subscription_flow setting and SubscriptionFlow (providers/llm/anthropic.rs), their tests, and the config schema snapshots.
• jp_llm: the SubscriptionFlow::Direct arms of credential resolution (provider/anthropic/resolve.rs), the Claude Code identity line and its override (CLAUDE_CODE_IDENTITY_LINE, IDENTITY_LINE_OVERRIDE in provider/anthropic.rs), and provider/anthropic/oauth.rs if nothing on the ACP path uses it.
• jp_cli: --direct and the direct --setup-token path of jp provider llm auth login (cmd/provider.rs).

To decide while doing it

• Stored conversations and config files that set subscription_flow = "direct" lose the field on load, so their subscription entries resolve through Claude Code instead. Warn when the field is dropped rather than switching routes silently.
• JP-stored Anthropic OAuth credentials become unused: leave them, or remove them on jp provider llm auth logout.
• RFD 110 describes direct as an explicit option; add a note to it.