feat: light, extensible first-run onboarding coachmarks (0206)

[crs48]

What

Light, lovely, non-blocking first-run onboarding — a few contextual tips that appear the first time you open a view, dismissible and never in the way. Implements exploration 0206.

Not a product tour. The research is lopsided (~70% skip linear tours; ~78% abandon by step three), so this is the modern coachmark pattern: one tip at a time, on first visit to a surface, Escape/✕/"Got it" to dismiss, replayable from Settings.

How it works

A declarative, plugin-extensible tip registry keyed by view. The "seen" set is persisted in the existing workbench store (xnet:workbench:v1) — the engine is a structural twin of the shipped What's-New plumbing. Zero new runtime dependencies (builds on the Base-UI Presence motion vocabulary + lucide-react + react-dom, all already present).

viewIdForPath(pathname) → useCoachmarks(view) → Coachmark (portal + Presence)
       route                registry +              non-modal card,
      segment            seenTips (store)          Esc / ✕ / "Got it"

The "grow with us" property: a feature or bundled plugin registers tips with contributeTips([...]) — the engine never changes. As the app pluginizes (0205), features bring their own onboarding.

Design choices

• Non-modal by design. Deliberately not a Base-UI Popover — a coachmark must never trap focus or block the app. It portals a fixed-position card next to its anchor (the editor's CommentPopover pattern), so the user's first action is never hijacked.
• One at a time, capped per session (≈2 new tips), so a long-dormant user reopening many views isn't buried.
• Dormant until hasOnboarded() — never piles on top of the welcome/auth flow.
• Reduced motion inherited from motion.css (no Framer Motion).
• Fails silent — a tip whose anchor isn't in the DOM simply waits for a later visit.

Changes

• apps/web/src/coachmarks/ — registry, useCoachmarks engine, Coachmark (+ story), useAnchorEl, view mapping, CoachmarkLayer, seed tips
• workbench store: seenTips + markTipSeen/resetTips
• Rail: data-coach anchors; Workbench mounts CoachmarkLayer (desktop + mobile)
• Settings: Tips & tours → Replay onboarding
• docs/ONBOARDING.md (how to add a tip) + changelog fragment

Seed tips

Command palette (⌘K) on Home, plus CRM, Tasks, and Discover — each anchored to its Rail icon.

Verification

• 19 new unit tests (registry purity, view mapping, engine serialization + per-session cap + versioned re-surface + enabled-gate, store seen-state, component dismiss via Got it / ✕ / Escape). Full apps/web dom suite green (144 tests); full repo suite green (8840 passed).
• Typecheck + eslint + prettier clean.
• Browser-verified the Coachmark in Storybook (renders, positions to anchor, "Got it" dismisses end-to-end); app boots with no console errors. (The passkey gate can't be passed headlessly, so per-view in-app confirmation is via Storybook + unit tests.)

🤖 Generated with Claude Code

[github-actions]

🖼️ UI changes in this PR

Components

🆕 Web/Coachmark — Below Anchor

🆕 Web/Coachmark — Command Palette

Screens

✏️ Settings _(SSIM 0.932)_

before	after	diff

_{Auto-captured by CI · run. Informational — not a blocking check.}

[github-actions]

Preview removed for PR #209.