[Feature] Support passing thinking effort via a CLI flag (e.g. --effort)

What feature would you like to see?

Support passing the thinking effort via a CLI flag for the current launch, e.g. kimi --effort low or kimi -p "..." --effort max, mirroring how -m/--model overrides the model per-launch.

Today effort can only be changed through config.toml ([thinking] effort, per-model default_effort / support_efforts, [secondary_model].default_effort) or the ACP protocol's set_config. There is no command-line or per-launch override, which makes it awkward to:

• run one-off kimi -p tasks with a different effort (e.g. cheap low for quick summaries, max for hard problems),
• temporarily try an effort without editing ~/.kimi-code/config.toml (then remembering to revert),
• set effort from scripts / CI.

Additional information

Verified against the source at @moonshot-ai/kimi-code@0.31.1 (matches installed v0.31.1):

• The full flag set is registered in apps/kimi-code/src/cli/commands.ts via Commander — no effort option exists.
• CLIOptions in apps/kimi-code/src/cli/options.ts has no effort field.
• allowUnknownOption(false) means --effort currently fails at startup with "unknown option".
• Official docs list no effort flag either: https://www.kimi.com/code/docs/en/kimi-code-cli/reference/kimi-command.html

Related: #1051 (TUI feedback for [thinking].effort) — related but distinct; this request is about a CLI/launch override.

Start in apps/kimi-code/src/cli/commands.ts, where Commander registers flags, and apps/kimi-code/src/cli/options.ts, where CLIOptions is defined. Trace how the existing -m/--model override reaches launch configuration, then determine where the effort value should be validated and applied. Update the official CLI reference page and verify that one-off commands accept --effort without editing config.toml.