fix(banner): update launch banner to "NEMO RELAY"

[bbednarski9]

Overview

Updates the CLI welcome banner from the old Flow wordmark to a centered ANSI Shadow NEMO RELAY banner while preserving the existing green styling, rounded border, and docked version tag behavior.

• I confirm this contribution is my own work, or I have the right to submit it under this project's license.
• I searched existing issues and open pull requests, and this does not duplicate existing work.

Details

• Replaces the existing banner art with ANSI Shadow-style NEMO RELAY text.
• Removes the experimental checkered flag columns from the banner.
• Centers the banner as a single FIGlet block so all rows share the same left edge.
• Keeps the existing plain-mode, color-mode, border, version tag, and cursor-control behavior.
• Adds a regression test that verifies the FIGlet rows are centered together as one block.

Where should the reviewer start?

Start with crates/cli/src/banner.rs for the rendering change, then review crates/cli/tests/coverage/banner_tests.rs for the centering regression coverage.

Related Issues: (use one of the action keywords Closes / Fixes / Resolves / Relates to)

• Relates to #

Summary by CodeRabbit

• Style
  • Updated the CLI banner with a new glyph layout design featuring improved visual appearance.
  • Improved horizontal centering of banner content within the display frame.

[coderabbitai]

Walkthrough

This PR updates the NeMo Relay CLI banner to center its figlet art within the rendered frame width. The banner art content is replaced with new ANSI-shadow filled-block glyphs, and the layout algorithm computes a centered column offset, padding each row accordingly rather than resizing. Tests verify the centering is consistent across all figlet rows and validate the updated appearance.

Changes

Banner Art Centering

Layer / File(s)	Summary
Banner art content and centering implementation crates/cli/src/banner.rs	Updated BANNER_LINES to new ANSI-shadow filled-block figlet layout (six rows), kept COL_END constant unchanged, and rewrote build_grid to center banner art by computing banner_art_width, deriving centered start_col via saturating_sub, and padding each row using new padded_row helper that places characters at the offset.
Test helpers and centering verification crates/cli/tests/coverage/banner_tests.rs	Introduced helper functions frame_grid_rows, frame_inner_width, and first_art_col to extract and analyze frame content. Enhanced render_frame_settled_contains_figlet_glyphs test to verify absence of flag-column patterns. Added figlet_rows_are_centered_as_one_block test to verify all figlet rows share the same computed centered left edge.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~12 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 40.00% which is insufficient. The required threshold is 80.00%.	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 with type 'fix', scope 'banner', and a concise imperative summary under 72 characters.
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.
Description check	✅ Passed	The pull request description follows the required template structure with all key sections completed: Overview with checkboxes confirmed, detailed Changes describing the banner update and centering logic, clear reviewer guidance pointing to specific files, and Related Issues section (though the issue number is incomplete).

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests

---

_{Comment @coderabbitai help to get the list of available commands and usage tips.}

[bbednarski9]

/merge