0001. Canonical product name and wordmark

Context

The product name drifts across the codebase:

Spelling	Where
`KLineChartQuant`	screenshot watermark (`useChartScreenshot.ts`), repo name
`KlineChartQuant`	on-chart brand link + aria-label (`KLineChart.vue`)
`KLineChart Quant`	desktop window title (`desktop-electron/index.html`)
`@363045841yyt/klinechart-*`	npm scope

Display name: KLineChartQuant — one word, capital K, L, C, Q. Used in UI, titles, docs, aria-labels, store listings.
Short name: KCQ — for favicon/app icon monogram, PWA short_name, subdomain (kcq.nebutra.com), tight UI.
Ecosystem form: KLineChartQuant by Nebutra when shown outside the product (Nebutra surfaces, marketing).
Wordmark: Outfit 600, the existing mark by 363045841. Brand VI derivatives (monogram, glyph, color) build on it; it is not redrawn.
Machine identifiers are unchanged: npm package names, repo URL, storage keys, and Electron productName (KLineChart Quant). Electron derives the userData directory from productName, so renaming it would orphan local data. Renaming any of these is a separate breaking-change decision.
Product strings come from one constant (BRAND in shared code) instead of literals.

Fix KlineChartQuant in KLineChart.vue and KLineChart Quant in the desktop window title.
The CI spelling check excludes electron-builder.yml productName.
Add a lint/grep check in CI rejecting KlineChartQuant and KLineChart Quant.