fix(tui): model-aware thinking levels, vscode truecolor, suppress reload banner

[elkaix]

Summary

• Scope GPT-5-family reasoning effort to each model's actually-supported levels so the selector and Shift+Tab cycle never offer (or send) levels the API rejects (e.g. minimal on gpt-5.4/5.5).
• Promote VS Code-family integrated terminals (TERM_PROGRAM=vscode) to truecolor so diff add/remove tints render correctly instead of falling back to the 16-color path.
• Skip the welcome banner on same-session reloads (/model, /theme, /new, fork, …) while keeping it for /clear and /reload.

Test plan

• tests/core/test_model_thinking_levels.py — GPT-5 reasoning matrix and clamping
• tests/ui_and_conv/test_terminal_capabilities.py — VS Code truecolor promotion
• tests/ui_and_conv/test_shell_run_placeholders.py — banner suppress on reload
• make check-pythinker-code && make test-pythinker-code (CI)

Summary by CodeRabbit

• New Features
  • Reasoning-effort selections are now clamped to the active GPT-5 model’s supported levels before submission.
• Bug Fixes
  • Diff cards no longer apply an opaque blue overlay; highlighted diffs strip background styling so terminal row/context tints display correctly.
  • VS Code–family terminals now correctly promote to truecolor for diff tinting.
  • Welcome-banner rendering is properly suppressed during reload flows when appropriate.
• Tests
  • Added regression coverage for per-model reasoning-level scoping, welcome-banner suppression, VS Code truecolor detection, and background-free diff highlighting.

[coderabbitai]

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• tests/utils/test_diff_render.py

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📝 Walkthrough

Walkthrough

Four independent fixes ship together: GPT-5-family thinking-effort levels are clamped per model version before reaching the API using new openai_gpt_reasoning_levels and available_model_thinking_levels helpers; color_depth() now promotes TERM_PROGRAM=vscode terminals to truecolor; in-session model/theme/thinking reloads suppress the welcome banner via a suppress_banner flag threaded through _reload_loop to Shell; and syntax-highlighted diff code no longer carries opaque background overlays, allowing terminal row tints to show correctly.

Changes

GPT-5 reasoning clamping, VS Code truecolor, and banner suppression

Layer / File(s)	Summary
GPT-5 reasoning-level helpers and model-aware clamping src/pythinker_code/llm.py, src/pythinker_code/soul/pythinkersoul.py, src/pythinker_code/ui/shell/slash.py, tests/core/test_model_thinking_levels.py	Introduces _GPT5_REASONING_RE, openai_gpt_reasoning_levels, and available_model_thinking_levels in llm.py; create_llm clamps thinking_effort to model-supported ladder via clamp_thinking_effort(..., available_model_thinking_levels(...)) when effort is explicitly requested; PythinkerSoul.available_thinking_efforts and /model//thinking slash commands derive options from model-scoped ladder; four tests verify per-version ladders, scoping fallback for non-GPT models, and clamping behavior.
VS Code terminal truecolor detection src/pythinker_code/ui/terminal_capabilities.py, tests/conftest.py, tests/ui_and_conv/test_terminal_capabilities.py	color_depth() adds TERM_PROGRAM=vscode → "truecolor" branch before TERM-based parsing; test conftest clears COLORTERM, WT_SESSION, and TERM_PROGRAM to stabilize color-tier testing; new test validates vscode promotion respects NO_COLOR/FORCE_COLOR precedence; 16-color fallback test extended to clear TERM_PROGRAM.
Welcome-banner suppression on non-clearing reloads src/pythinker_code/ui/shell/__init__.py, src/pythinker_code/app.py, src/pythinker_code/cli/__init__.py, tests/ui_and_conv/test_shell_run_placeholders.py	Shell.__init__ accepts suppress_banner: bool = False and guards _print_welcome_info in run(); PythinkerCLI.run_shell threads flag to Shell; _reload_loop initializes suppress_banner=False and flips it to not e.clear_screen on Reload exceptions, so non-clearing reloads skip the splash; two tests assert banner prints once by default and is suppressed when flag is True.
CHANGELOG CHANGELOG.md	Documents reasoning-effort clamping, diff background removal, VS Code truecolor detection, and banner suppression behavior in Unreleased section.

Diff background color stripping

Layer / File(s)

Summary

Background removal from highlighted diff code src/pythinker_code/utils/rich/diff_render.py, tests/utils/test_diff_render.py

Adds Span import and _without_bg and _strip_background helpers to remove background colors from RichStyle and Text spans; highlight_diff_code strips backgrounds from both text style and all spans while preserving foreground colors and trailing-newline cropping behavior; test asserts syntax-highlighted code carries no background styling (bgcolor is None) while foreground colors remain; autouse fixture isolates active code theme across test runs to prevent cross-test contamination.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~25 minutes

Possibly related PRs

• Pythoughts-labs/pythinker-code#62: Both PRs modify welcome banner rendering in src/pythinker_code/ui/shell/__init__.py — this PR adds suppress_banner gating to avoid duplicate banners on reloads; PR #62 adjusts banner content, styling, and lifecycle behavior.

Suggested labels

bug

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 54.05% which is insufficient. The required threshold is 70.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title follows conventional commits format (type: fix, scope: tui) and accurately summarizes the three main changes: model-aware thinking levels, VS Code truecolor support, and suppress reload banner.
Description check	✅ Passed	The description provides a clear summary of changes with detailed explanations and includes a comprehensive test plan; all required checklist items are either marked complete or noted as pending CI.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/shell-thinking-vscode-banner

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[codecov]

Codecov Report

❌ Patch coverage is 77.27273% with 5 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
src/pythinker_code/utils/rich/diff_render.py	72.72%	1 Missing and 2 partials ⚠️
src/pythinker_code/app.py	0.00%	1 Missing ⚠️
src/pythinker_code/ui/shell/slash.py	75.00%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!

[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@tests/utils/test_diff_render.py`:
- Around line 667-670: The test mutates the global code theme by calling
set_active_code_theme("catppuccin-adaptive") without restoring it, which can
cause test-order coupling. Add a new autouse fixture named
_restore_active_code_theme that saves the current active code theme before the
test runs using get_active_code_theme(), yields to allow the test to execute,
and then restores the original theme in a finally block using
set_active_code_theme(). This fixture should import get_active_code_theme and
set_active_code_theme from pythinker_code.utils.rich.syntax, following the same
pattern already demonstrated in tests/ui_and_conv/test_code_theme_opt_in.py.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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• CHANGELOG.md
• src/pythinker_code/utils/rich/diff_render.py
• tests/utils/test_diff_render.py