WebShell model reasoning preferences

Goal

WebShell keeps the selected model and reasoning preference across daemon sessions without creating an empty session from the Welcome screen. The first prompt remains the session-creation boundary.

This change uses the existing model.reasoningEffort setting. It does not add a second reasoning-enabled setting and does not change provider request mapping or the public ACP protocol.

Stored values

model.reasoningEffort has one meaning at every daemon boundary:

• an absent value uses the target model's default thinking behavior;
• none disables thinking;
• low, medium, high, xhigh, or max enables thinking at that tier.

default is a control command only. It removes the stored value and resets the live session to the model default. It is never stored and is never rendered as an effort choice.

The Core ReasoningEffort type remains the five strict tiers. none and default are represented only by the daemon and settings boundary type.

Session lifecycle

Before a session exists, WebShell keeps the selected model and reasoning value in component state. Sending the first prompt performs these operations in order: create, attach, set model, persist reasoning, then submit the prompt.

For a regular live session, WebShell sends reasoning changes immediately with persist: true. Managed standalone conversations keep their existing session-only settings boundary and use persist: false. WebShell updates its state only from the daemon's confirmed configOptions response. The session owns preference writes and rollback across writable scopes; a failed write also restores the live overrides. Model reconciliation reuses the same reset operation. Requested persistence completes before the daemon reports success.

Turning thinking off sends none. Turning it on again sends default, which removes none and uses the model default instead of restoring the old tier.

Capability reconciliation

Every model switch reconciles the stored selection against the target model:

• a supported tier and an allowed none value are retained;
• an unsupported tier is removed and the live override is reset;
• a toggle-only model retains only none when disabling is allowed;
• a model without reasoning controls removes every explicit selection;
• mandatory thinking removes none.

There is no fallback or tier clamping at this layer. Once an incompatible selection is removed, switching back does not restore it.

Session-only ACP model changes clear incompatible live overrides without changing the shared stored preference. Only a persistent model selection may remove it from writable settings scopes.

Welcome uses model-specific workspace previews. Once a session exists, WebShell renders reasoning controls only from that session's authoritative configOptions.

UI and localization

Tiered models render only the real advertised tiers. Toggle-only models render only the thinking switch: no effort heading, effort row, or Default choice is present in the DOM. Unsupported models render no reasoning section.

WebShell translates the five fixed effort values itself in English and Chinese and never renders daemon-provided English labels.