feat(shell): default show_thinking_stream to true

[RealKai42]

Summary

• Flip the default of show_thinking_stream from false to true so fresh installs see the streaming reasoning preview out of the box
• Users who prefer the compact 1.32-style indicator can set show_thinking_stream = false in their config
• Updates config default, docs (EN/ZH), example TOML, default-config snapshot test, and Unreleased changelog entries

Test plan

• uv run pytest tests/core/test_config.py::test_default_config_dump passes with the new snapshot
• Manual: start a fresh session without any config override and confirm the streaming reasoning preview shows up during thinking blocks

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[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 1 additional finding.

[Copilot]

Pull request overview

This PR flips the default for the shell UI’s show_thinking_stream config so new installs show the streaming “thinking” preview by default, while still allowing users to opt back into the compact 1.32-style indicator.

Changes:

• Set Config.show_thinking_stream default from false → true.
• Update the default-config snapshot test to match the new default.
• Update EN/ZH configuration docs and release notes/changelog entries to reflect the new default.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
src/kimi_cli/config.py	Changes the config default and updates the config field description accordingly.
tests/core/test_config.py	Updates the default config dump snapshot expectation to show_thinking_stream: True.
CHANGELOG.md	Adds an Unreleased entry documenting the default flip.
docs/en/release-notes/changelog.md	Reflects the Unreleased changelog entry in the docs site changelog.
docs/zh/release-notes/changelog.md	Adds the corresponding translated Unreleased changelog entry.
docs/en/configuration/config-files.md	Updates the documented default value and example config snippet.
docs/zh/configuration/config-files.md	Updates the documented default value and example config snippet (ZH).

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