feat(cli): add Weaver, a block-art terminal mascot

[Agnik47]

Description

Gives webcmd a mascot: Weaver, a chunky block spider who drops in on a thread when you install webcmd, and stands beside the wordmark in the help banner.

The character argues for itself on product grounds, not only on taste — a spider that crawls a site once and weaves what it learns into its web is sitemap memory, so it draws "explore once, execute forever" without a sentence of explanation.

Related issue: #510

What changed

• src/mascot.ts (new) — the art, seven frames, renderer, animator. Pure; no I/O beyond an injected writer.
• src/brand.ts — ACCENT_RGB / SHADE_RGB move here so #56C5FF is declared once and shared with the help banner rather than a fourth copy.
• src/command-presentation.ts — ROOT_HELP_BANNER_PARTS gains a third column for the sprite. Banner width becomes 73 display columns (wordmark 52 + 2 gutter + mascot 18), inside the 80 budget. The Hangul-filler spacer row is left exactly as wide as it was.
• scripts/postinstall.js — animates the drop on a global install, above the existing "Next step" block.
• src/hosted/setup.ts — greets first-run setup.
• docs/webcmd-weaver.svg (new) — vector twin, generated from the same sprite so the terminal character and the illustrated one cannot drift.

Two constraints worth calling out for review

The art is filled block glyphs, not box-drawing outlines. Each part of Weaver is a different character (█ body, ▓ legs, ● eyes) rather than one character recolored. That keeps color purely additive, which is what preserves the invariant at command-presentation.test.ts:170 — stripping ANSI from a colored help screen returns the plain one byte for byte. All 14 existing banner tests pass untouched, including the local/hosted byte-identity assertions in hosted/runner.test.ts.

Animation is gated on the output stream being a TTY, not on prompting being possible. setup.ts's existing canPrompt() returns true whenever a question fn is injected, even with no terminal attached; animating on that broke does not resolve until all caller-owned output writes complete, which asserts exact write counts. A separate canAnimate() checks the stream instead — the more correct condition, since an injected prompt says nothing about whether a cursor can be moved. Every existing setup test passes unmodified.

Escape hatches: piped installs get one static frame with no escapes, CI gets nothing (the existing process.env.CI guard), NO_COLOR drops color, and WEBCMD_NO_MASCOT=1 opts out entirely.

Type of Change

• 🐛 Bug fix
• ✨ New feature
• 🌐 New site adapter
• 📝 Documentation
• ♻️ Refactor
• 🔧 CI / build / tooling

Checklist

• I ran the checks relevant to this PR
• I updated tests or docs if needed
• I included output or screenshots when useful
• If I edited skill-src/, I ran make build and committed skills/ — n/a, no skill changes

Verification

npm run typecheck clean. npm run build clean.

npx vitest run --project unit src/mascot.test.ts src/postinstall.test.ts \
  src/command-presentation.test.ts src/hosted/setup.test.ts
→ Test Files  4 passed (4)
        Tests  75 passed (75)

14 new tests in src/mascot.test.ts cover:

• every frame is the same height and width, or the \x1b[<n>A redraw tears mid-animation
• the plain render contains no escapes, and the colored render strips back to it exactly
• the cursor is restored even when a write throws mid-animation
• the frames inlined in scripts/postinstall.js match WEAVER_FRAMES — that script must run with no build step, so it cannot import the module, and this is the guard against the copies drifting

Note on the wider suite: npm test shows unrelated pre-existing failures on Windows (EBUSY unlinking chrome_debug.log in the browser runner tests, plus temp-dir contention). I reproduced 28 of them on a clean checkout of main with this branch stashed, so they are environmental rather than introduced here.

Screenshots / Output

webcmd --help:

    ▓▓      ▓▓      ██╗    ██╗███████╗██████╗  ██████╗███╗   ███╗██████╗
    ██████████      ██║    ██║██╔════╝██╔══██╗██╔════╝████╗ ████║██╔══██╗
  ▓▓██ ●  ● ██▓▓    ██║ █╗ ██║█████╗  ██████╔╝██║     ██╔████╔██║██║  ██║
  ▓▓██  ▾   ██▓▓    ██║███╗██║██╔══╝  ██╔══██╗██║     ██║╚██╔╝██║██║  ██║
    ██████████      ╚███╔███╔╝███████╗██████╔╝╚██████╗██║ ╚═╝ ██║██████╔╝
 ▓▓  ▓▓    ▓▓  ▓▓    ╚══╝╚══╝ ╚══════╝╚═════╝  ╚═════╝╚═╝     ╚═╝╚═════╝
ㅤ
  Make any website your CLI. Zero setup. AI-powered.

Final frame of the install greeting:

        ││        
        ││        
        ││        
    ▓▓      ▓▓    
    ██████████    
  ▓▓██ ●  ● ██▓▓  
  ▓▓██  ▾   ██▓▓  
    ██████████    
 ▓▓  ▓▓    ▓▓  ▓▓ 
  Webcmd installed. Weaver crawls a site once so your agents never have to rediscover it.

Blink frame — ● becomes ─, and the leg rows shift one column as he lands:

    ▓▓      ▓▓            ▓▓        ▓▓   
    ██████████            ██████████     
  ▓▓██ ●  ● ██▓▓        ▓▓██ ─  ─ ██▓▓   
  ▓▓██  ▾   ██▓▓        ▓▓██  ▾   ██▓▓   
    ██████████            ██████████     
 ▓▓  ▓▓    ▓▓  ▓▓        ▓▓ ▓▓    ▓▓ ▓▓  

Happy to change the character, the palette, or drop any of the three surfaces — the art lives behind one module, so placement is easy to trim.

🤖 Generated with Claude Code

https://claude.ai/code/session_013dvZ6uiCdQmpUTTiQ2XJZL

[github-actions]

🟠 Maintainer review suggested — low confidence

The automated review could not reach a fully supported conclusion.

This review is advisory and does not block merging.