patties.config.ts — optional `ui` block

Purpose

shadcn centralizes UI scaffolding config in components.json. patties replaces that with fixed conventions (app/components/ui/, _internal/, app/styles/tokens.css, CSS-vars always on, lucide-react, no RSC toggle). The parity matrix records that stance as a deliberate divergence — less surface, no config drift — but flags one real cost: shadcn's --path flexibility, the one hard-coded convention users miss immediately (matrix §3 "Takeaway", §2 --path).

This spec adds a narrow, optional ui block to patties.config.ts so that the two paths that genuinely vary between projects — where component source is stamped and where tokens live — can be redirected, without reintroducing a full components.json. Everything not listed here stays convention, not config.

Non-goals (kept as convention, not config)

These remain fixed; we are not porting components.json wholesale:

• aliases — import paths are derived from componentsDir, not separately configurable. (matrix §3: divergent)
• cssVariables on/off, style, baseColor, rsc, tsx — patties is always CSS-vars-on, single-style, SSR-island, .tsx. (matrix §3: divergent)
• iconLibrary — lucide-react is fixed; userland swaps icons by editing stamped source. (matrix §3: n/a)

If a future RFC wants any of these configurable, it extends this block — but the default of "no config needed" must survive.

Schema

The ui block is fully optional. Absent config behaves exactly as today.

// src/config/schema.ts (Zod)
const UiConfig = z
  .object({
    // Where `patties add` stamps component source. Default: "app/components/ui".
    componentsDir: z.string().default("app/components/ui"),
    // Where shared helpers (_internal/cn, slot, variants) are stamped.
    // Default: "<componentsDir>/_internal".
    internalDir: z.string().optional(),
    // Where the token CSS is merged. Default: "app/styles/tokens.css".
    tokensFile: z.string().default("app/styles/tokens.css"),
  })
  .strict()
  .optional();

• All paths are resolved relative to the project root (the dir holding patties.config.ts), never absolute, never ..-escaping the project — the loader rejects paths that resolve outside the project root (EXIT.USAGE).
• internalDir defaults to <componentsDir>/_internal so redirecting componentsDir keeps helpers co-located without a second setting.

Resolution & precedence

patties add resolves effective paths in this order (first wins):

1. --path <dir> CLI flag (per [[cli/14-add-path]]) — affects componentsDir only, for one invocation.
2. config.ui.componentsDir / internalDir / tokensFile.
3. The hard-coded convention defaults above.

The add pipeline (stamper.ts, internal.ts, tokens.ts) currently hard-codes these destinations; this spec threads a resolved UiPaths object through them instead of string literals.

Manifest / agent-md

No manifest change. The ui block is read by the CLI add pipeline only; it is not part of route/island discovery and does not appear in the generated CLAUDE.md manifest section.

Acceptance criteria

• With no ui block, patties add button stamps to app/components/ui/button.tsx and app/components/ui/_internal/cn.ts, tokens to app/styles/tokens.css — byte-identical to today.
• With ui: { componentsDir: "src/ui" }, patties add button stamps to src/ui/button.tsx and helpers to src/ui/_internal/.
• With ui: { tokensFile: "styles/theme.css" }, the token merge targets that file and is idempotent on re-run.
• A componentsDir that resolves outside the project root exits EXIT.USAGE with a one-line message; no files are written.
• config.ui is .strict() — an unknown key (e.g. aliases) is a config error, pointing the user at the convention it replaces.
• bun run typecheck passes; the config Zod schema infers the optional ui shape.