Feature/add app config

[srcdev]

## Summary

Introduces `app.config`-based defaults for four components — `DisplayDialog`, `DisplayPrompt`, `DisplayToast`, and `AlertContentInner` — so consumers can configure site-wide behaviour once in their own `app.config.ts` instead of repeating props at every usage site.

## Changes

- **`app/app.config.ts`** (new) — Layer defaults for all four components under the `srcdev.*` namespace. Nuxt deep-merges consumer overrides at build time.
- **`app/types/app-config.d.ts`** (new) — `AppConfigInput` module augmentation so consumer `defineAppConfig` calls are fully type-safe.
- **`DisplayDialog.vue`** — Props that had hardcoded `withDefaults` values now default to `undefined`; a `resolved` computed object applies the prop → app.config → fallback chain. `closeIcon` is now configurable.
- **`DisplayPrompt.vue`** — Same `resolved` computed pattern; `theme`, `dismissible`, `useAutoFocus`, and `masked` are all app.config-configurable.
- **`DisplayToast.vue`** — App.config fallback inserted into existing individual computed props (`theme`, `position`, `alignment`, `fullWidth`, `masked`, `autoDismiss`, `duration`, `revealDuration`). Per-instance `content` and `returnFocusTo` are excluded.
- **`AlertContentInner.vue`** — Theme icons and dismiss icon now resolved via `app.config.srcdev.alertContent`; one config change covers every toast, prompt, and alert in the app.
- **`.gitignore`** — Added `.claude/projects/` to prevent machine-specific Claude session data leaking into the repo.
- **`.claude/skills/`** — Skill docs updated/added for all four components documenting the app.config defaults section and resolution chain.

## Testing

- All existing unit tests pass (`npm run test:run`).
- Resolution chain (explicit prop wins over app.config wins over hardcoded fallback) verified manually.
- Boolean props use explicit `undefined` defaults in `withDefaults` to prevent Vue's boolean-casting from swallowing absent values before the `??` fallthrough fires.

## Notes

- `undefined as SemanticTheme | undefined` type assertion is required in `defineAppConfig` for optional fields that can be `undefined` — without it, Nuxt's generated `AppConfig` type omits the key entirely.
- The `alertContent` key is intentionally separate from `displayToast` because `AlertContentInner` is shared infrastructure beneath `AlertContent`, `AlertMaskedContent`, `DisplayToast`, and `DisplayPrompt`.

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Project	Deployment	Actions	Updated (UTC)
srcdev-design-system	Ready	Preview, Comment	Jun 20, 2026 4:28pm
srcdev-design-system-storybook	Ready	Preview, Comment	Jun 20, 2026 4:28pm

[Copilot]

Pull request overview

Adds app.config-driven defaults under srcdev.* so consumers can set global behavior/appearance for DisplayDialog, DisplayPrompt, DisplayToast, and AlertContentInner once, while preserving per-instance overrides.

Changes:

• Introduces layer-level app.config defaults and Nuxt AppConfigInput type augmentation for srcdev.*.
• Updates the four components to resolve values via explicit prop/config → app.config → hardcoded fallback.
• Updates repo hygiene/docs (.gitignore, .claude/skills/*) to document the new configuration surface.

Reviewed changes

Copilot reviewed 10 out of 12 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
app/types/app-config.d.ts	Adds AppConfigInput augmentation for typed srcdev.* defaults.
app/components/02.molecules/alert-content/AlertContentInner.vue	Resolves theme/dismiss icons via app.config.srcdev.alertContent.
app/components/01.atoms/toast/DisplayToast.vue	Adds app.config.srcdev.displayToast fallbacks into computed appearance/behavior values.
app/components/01.atoms/prompt/DisplayPrompt.vue	Implements a resolved computed to apply prop → app.config → fallback resolution.
app/components/01.atoms/display-dialog/DisplayDialog.vue	Implements a resolved computed and makes close icon configurable via resolved config.
app/app.config.ts	Provides layer default values for all four components under srcdev.*.
.gitignore	Ignores Claude session project data (.claude/projects/).
.claude/skills/index.md	Adds index entry for AlertContentInner docs.
.claude/skills/components/display-toast.md	Documents app.config defaults + resolution chain for DisplayToast.
.claude/skills/components/display-prompt.md	Documents app.config defaults + resolution chain for DisplayPrompt.
.claude/skills/components/display-dialog.md	Documents app.config defaults + closeIcon behavior for DisplayDialog.
.claude/skills/components/alert-content-inner.md	New doc describing global icon configuration via app.config.

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