docs(dte): document thinking effort

[easonLiangWorldedtech]

Documentation for the Dynamic Thinking Effort (DTE) series. Companion to the trial VSIX review build.

New pages

• Thinking Effort (Features) — the four UI surfaces (composer toggle, task header chip, in-chat display, subtask start effort), effort levels and precedence, the Model Reasoning Effort profile setting, model-driven changes and guardrails, and declaring supported levels for self-hosted models. Persistence semantics are explicit: the task-local override is stored with the task (restored when the task is reopened from history) and is never written to the provider settings.
• set_thinking_effort (Available Tools) — tool reference following the existing tool-doc skeleton: parameters, behavior, when it is used, guardrails (capability clamp, oscillation refusal, escalation cap of 3 upward changes per task), and usage examples.

Wiring

• sidebars.ts — both pages added to their categories.
• experimental-features.md — Dynamic Thinking Effort listed, with a note that the setting gates the model-driven tool only (the chat UI surfaces are capability-gated and work with the setting off).
• the-chat-interface.md — composer thinking effort selector documented.
• new-task.md — optional thinking_effort parameter documented.
• features/index.md — Thinking Effort link added.

Provider pages

• OpenAI Compatible — declaring supported reasoning effort levels: which levels unlock the controls, and the current scope (the selected level is not yet sent to the server with each request).
• Ollama — the pre-existing reasoning effort wire through the think parameter, including the Extra High/Max to High mapping.
• LM Studio — note that the LM Studio page does not expose the declaration, and how to use it via the OpenAI Compatible provider instead.

Images

• Three gallery captures under static/img/thinking-effort/ (composer menu, header chip, F7 declaration), each with a one-line caption per repo conventions.

Verification

• pnpm build passes with no warnings (Docusaurus; also re-run by the repo's pre-commit hook).
• All internal links resolve to existing docs.
• No version numbers in general docs; no banned words in new content.
• Every behavioral claim was checked against the trial branch code (task-local state, guardrail constants, i18n strings, provider request builders).