Design QA: Spacing + Font modes (side panel)

[sm17p]

Summary

Epic for Spacing QA and Font QA modes in the side panel: scan → catalog with counts → select bucket → highlight all matches. Spec and decisions live on GitHub (this epic + children); there is no separate PRD file in the repo.

Child issues

• Design QA | Spacing QA mode (catalog + highlight) #60 — Spacing QA mode (catalog + highlight)
• Design QA | Font QA mode (catalog + highlight) #61 — Font QA mode (catalog + highlight)
• Side panel: allow Design QA modes without active tracker #62 — Side panel: allow Design QA without active tracker (prerequisite for full UX)

Related issues

• Shell / tabs: Add sidepanel  #13
• Viewport resize (highlights + panel): Handle viewport resize #7
• Scroll alignment for overlays: Update tracker position on scroll #12
• Shortcuts vs panel typing: Shortcuts buggy when typing onscreen #14

Acceptance (high level)

• Spacing QA: Margin/padding toggles; catalog with counts; select row highlights matches in scope; clear removes highlights; viewport-only + performance caps per implementation notes on child issues.
• Font QA: Normalized typography catalog; select row highlights matches; trivial font-family variants collapse to one row.
• Resize / scroll / shortcuts: Aligned with Handle viewport resize #7, Update tracker position on scroll #12, Shortcuts buggy when typing onscreen #14.
• Without tracker: QA usable without a selected element (Side panel: allow Design QA modes without active tracker #62).

[sm17p]

Child issues: #60 (Spacing QA), #61 (Font QA). Gate: #62 (ungated QA access).