Add DS::Pill component to consolidate scattered pill/badge patterns

[gariasf]

Add a DS::Pill component

We don't have a shared pill/badge component in the DS namespace, so pill-shaped UI is reinvented across many partials with inconsistent classes. A few callsites also break the design-token rule (text-green-500 instead of text-success) and a few have failing WCAG AA contrast (text-on-own-tint pattern).

Proposed API

DS::Pill.new(
  variant: :neutral | :success | :warning | :error,
  label: String,
  dot: true | false,            # coloured semantic dot
  size: :sm | :md
)

Default visual (variant A from the contrast review): bg-surface-inset text-primary + a small coloured dot when dot: true. The dot carries the semantic meaning, the label sits in the high-contrast neutral pill — ships AA contrast for free, matches the existing _maturity_badge look.

Callsites to consolidate

Pill markup in the wild today:

• app/views/settings/providers/_status_pill.html.erb
• app/views/settings/providers/_maturity_badge.html.erb
• app/views/shared/_badge.html.erb (uses raw text-green-500 etc — also breaks DS-token rule)
• app/views/shared/_color_badge.html.erb
• app/views/categories/_badge.html.erb
• app/views/accounts/_tax_treatment_badge.html.erb (+ inline twin in app/views/reports/_investment_performance.html.erb:121)
• app/views/import/qif_category_selections/show.html.erb:86 (inline, low contrast)
• app/views/sophtron_items/_sophtron_item.html.erb:26 (inline, low contrast)
• app/views/transactions/_transaction.html.erb (lines 92, 101, 106, 115 — pending / review-recommended / potential-duplicate / split badges)
• app/views/transactions/_split_parent_row.html.erb:39
• app/views/transactions/_header.html.erb:25
• app/views/transactions/_transfer_match.html.erb (lines 9, 12)
• app/views/transactions/searches/filters/_badge.html.erb
• app/views/investment_activity/_badge.html.erb
• app/views/investment_activity/_quick_edit_badge.html.erb:52
• app/views/simplefin_items/_activity_badge.html.erb
• app/views/budget_categories/_budget_category.html.erb:71
• app/views/settings/preferences/show.html.erb (lines 65, 70, 170)

Out of scope

The immediate WCAG AA contrast fix on the providers settings status pill ships in PR #1710 by switching _status_pill to the variant-A look using existing tokens. This issue is the broader DS work to extract + unify.

Acceptance

• DS::Pill ViewComponent + Lookbook preview
• All callsites listed above migrated (or explicitly excluded with rationale)
• No raw colour utilities (text-green-500 etc) remain in pill callsites
• Existing visual regression set passes

[gariasf]

Quick note — DS::Pill now exists in main (shipped in #1829 as the Beta/Canary stage marker). It's structurally adjacent but not the same shape as what this issue proposes:

	Existing DS::Pill (#1829)	Proposed here (#1751)
Use case	Stage marker (Beta, Canary, future NEW / PRO / EXPERIMENTAL)	Status / category badge
Tones	violet, indigo, fuchsia, amber, gray	neutral, success, warning, error
Typography	uppercase, 10/11px, tracking-wide	normal case, label-sized
Styles	soft / filled / outline	soft (single style)
Modes	with-dot, dot-only	with-dot, dot-only would still apply

So the question is whether to extend DS::Pill (add the semantic tones + a non-uppercase marker: false mode + a label size) or to add a sibling DS::Badge. Leaning extend — the API is already half-there and the visual difference is one boolean + a tone-table addition — but flagging for review since the existing Pill is fresh.

Will park this until the a11y audit children (#1738–#1747) are landed, then come back with a concrete proposal.