feat(banner): adopt CoDev Code's "codev" wordmark, theme-aware

[quickbeard]

What

Replaces the block CODEV ASCII logo with CoDev Code's lowercase "codev" pixel wordmark (ported verbatim from codev-code/packages/tui/src/logo.ts), and makes it light/dark aware.

• "co" on the left, "dev" on the right, bold, no drop shadow.
• "dev" is always the brand red #ee0033.
• "co" is the brand navy #19224c on a light terminal (matching CoDev Code's TUI mode === "light" branch) and the terminal's default foreground on a dark or unknown one — the readable counterpart of navy-on-white, mirroring how CoDev Code's own CLI banner handles the undetectable case.
• Keeps the AI Coding Agent Hub v<version> subtitle.

Rendered

Dark / unknown terminal — co in default foreground, dev red:

          ▄
█▀▀▀ █▀▀█ █▀▀█ █▀▀█ █  █
█    █  █ █  █ █▀▀▀ █  █
▀▀▀▀ ▀▀▀▀ ▀▀▀▀ ▀▀▀▀  ▀▀
AI Coding Agent Hub v0.5.2

Light terminal (COLORFGBG=0;15) — co switches to brand navy, dev stays red.

New: theme detection

src/lib/terminal-theme.ts#terminalIsLight — a synchronous, best-effort light/dark detector via COLORFGBG, the only signal available without an escape-sequence round trip that would fight Ink for the TTY. Returns true/false/null; on null (unknown) the banner falls back to the always-readable default foreground.

Note on limits: COLORFGBG isn't set by every terminal (iTerm2, macOS Terminal don't), so on those the banner uses the default-foreground fallback and only upgrades "co" to navy when a light background is explicitly advertised. The full navy-on-light / foreground-on-dark split is only guaranteed inside CoDev Code's TUI, which has a real theme context this CLI does not.

Tests

• Banner.test.tsx updated to assert the new wordmark glyphs.
• New tests/lib/terminal-theme.test.ts covering light/dark/rxvt fg;default;bg/unset/malformed cases.

Validation

pnpm fix, pnpm typecheck, pnpm test (1256 passed), and pnpm build && node dist/index.js --version all pass (also enforced by the pre-commit hook).

🤖 Generated with Claude Code