chore(2nd-gen): review and apply code standards across all components

[Rajdeepc]

Summary

Audited and standardized code patterns across all 2nd-gen base classes and SWC components, using Badge as the canonical reference implementation. This brings consistency to section headers, JSDoc tags, type patterns, CSS class naming, and other conventions.

Changes by category

Structural consistency

• Added API TO OVERRIDE / SHARED API / IMPLEMENTATION section headers to DividerBase and AlertBannerBase
• Standardized Divider's styles declaration from static property to getter (matching Badge, StatusLight, ProgressCircle, Asset)

CSS class naming

• Renamed Asset CSS classes from spectrum-* to swc-* prefix (matching all other 2nd-gen components)

JSDoc standardization

• Added @slot, @attribute, and @fires tags to DividerBase and AlertBannerBase
• Removed incorrect @element tag from DividerBase (belongs only on SWC subclass)
• Replaced @param JSDoc tags with standard property docs in AlertBannerBase
• Fixed extra space before @example in StatusLight

Type patterns

• Removed redundant : ElementSize[] type annotations from STATUSLIGHT_VALID_SIZES and PROGRESS_CIRCLE_VALID_SIZES (keep as const satisfies only)
• Added as const satisfies readonly string[] to DIVIDER_STATIC_COLORS and ASSET_VARIANTS
• Extracted AlertBanner.types.ts from inline module-level constants, with deprecated AlertBannerVariants alias for 1st-gen compatibility

Mixin usage

• Passed STATUSLIGHT_VALID_SIZES explicitly to SizedMixin in StatusLightBase (matching Badge and Divider patterns)

Cleanup

• Fixed typo: "exisit" → "exist" in observe-slot-text.ts
• Updated copyright year from 2025 to 2026 in postcss-token/index.d.ts and screen-reader-addon/register.tsx

Files changed (16)

File	Change
core/components/alert-banner/AlertBanner.base.ts	Section headers, JSDoc, types import
core/components/alert-banner/AlertBanner.types.ts	New — extracted types and constants
core/components/alert-banner/index.ts	Re-export types
core/components/asset/Asset.types.ts	as const satisfies
core/components/divider/Divider.base.ts	Section headers, JSDoc, remove @element
core/components/divider/Divider.types.ts	as const satisfies
core/components/progress-circle/ProgressCircle.types.ts	Remove redundant type annotation
core/components/status-light/StatusLight.base.ts	Explicit validSizes in SizedMixin, @attribute tag
core/components/status-light/StatusLight.types.ts	Remove redundant type annotation
core/mixins/observe-slot-text.ts	Fix typo
swc/components/asset/Asset.ts	spectrum-* → swc-* class prefix
swc/components/asset/asset.css	spectrum-* → swc-* selectors
swc/components/divider/Divider.ts	styles property → getter
swc/components/status-light/StatusLight.ts	Fix @example spacing
tools/postcss-token/index.d.ts	Copyright 2025 → 2026
.storybook/addons/screen-reader-addon/src/register.tsx	Copyright 2025 → 2026

Test plan

• 2nd-gen build passes (yarn build:2nd-gen)
• 1st-gen build passes (yarn build:1st-gen) — backward-compatible AlertBanner type alias verified
• All linters pass (ESLint, Stylelint, Prettier via pre-commit hooks)
• CI tests pass
• VRT confirms no visual regressions (Asset CSS rename)

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Latest commit: d47aaea

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📚 Branch Preview Links

• Documentation Site (first-gen)
• Storybook (first-gen)
• Storybook (second-gen)

🔍 First Generation Visual Regression Test Results

When a visual regression test fails (or has previously failed while working on this branch), its results can be found in the following URLs:

• Spectrum | Light | Medium | LTR
• Spectrum | Dark | Large | RTL
• Express | Light | Medium | LTR
• Express | Dark | Large | RTL
• Spectrum-two | Light | Medium | LTR
• Spectrum-two | Dark | Large | RTL
• High Contrast Mode | Medium | LTR

Deployed to Azure Blob Storage: pr-6091

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