defineClientConfig, defineRscConfig, defineSharedConfig for the
new multi-file admin config architecture.

Rows no longer need to wait for server roundtrip since form state
endpoint was removed.

Adds payload.config.shared.ts, payload.config.client.ts,
payload.config.rsc.tsx with custom components and validators.
Also adds blocks and array fields to Posts collection.

Layout imports RSC config and passes to RootLayout.
ClientConfigBridge imports client + shared configs,
merges them, and provides via React context.

…ons (Option C)

The config types now support four sections:
- admin: admin-level components (logo, nav, views, etc.)
- collections: per-collection components (beforeList, edit buttons, etc.)
- globals: per-global components (elements, views, etc.)
- fields: field-level components keyed by schema path

Merges client and RSC configs into a single no-directive file that
can hold RSC components, client components, and client functions.
Shared config uses 'use client' so validators serialize across RSC
boundary while remaining executable in Node.js.

Threads adminConfig through handleServerFunctions like importMap was.

Architecture:
- payload.config.admin.client.tsx ('use client') for client components + functions
- payload.config.admin.rsc.tsx (no directive) for RSC components
- payload.config.shared.ts (no directive, optional) for shared validators
- Shared config auto-merged into client config via ClientConfigBridge
- RSC components rendered on-demand via render-admin-rsc server action
- Client components render immediately, no server roundtrip
- rscSchemaPaths metadata tells client which fields need server action

setAdminConfig() called in RootLayout, getAdminConfig() available
to all server components in the render tree for resolving admin-level
RSC components without threading props through every view.

- Created payload.config.admin.rsc.tsx and payload.config.admin.client.tsx
- Removed string-path component references from config.ts and all
  collection/global configs
- Fixed RSC serialization: don't pass rscAdminConfig to RootProvider,
  use server-side cache (getAdminConfig) instead
- rscSchemaPaths passed as serializable string[] for client-side checks

Admin-level components (nav hooks, logout, settings, views) must be
in the RSC config since they're rendered by Server Components.
Client config now only holds field-level overrides.
Also removed rscAdminConfig from RootProvider props to avoid
RSC serialization errors.

Fixed getCustomViewByRoute, isCustomAdminView, getDocumentView,
getMetaBySegment, and Versions metadata to read views and meta
from admin config instead of config.admin.components.

Pass component functions with clientProps instead of pre-rendered JSX.
This allows on-demand rendering with proper props.

getTabs now checks admin config views first for tab configuration,
including custom tab labels, components, order, and paths.

…nput/AfterInput

Custom field components from admin config now receive field, path,
and schemaPath props so they can access field configuration.

…custom Field

When a custom Field component is set alongside Label/Description
overrides, render them all in a wrapper div.

…TDZ error

…igation

React cache() is per-request. On client-side navigation, new server
requests don't go through RootLayout, so the admin config cache was
empty. Now handleServerFunctions also sets the cache.

…he()

React cache() is per-request and doesn't persist across client
navigations. Module-level state persists across all requests
within the same process.

- generateSchemaPathTypes now outputs SchemaPathMap interface mapping
  every schema path to its field type ('text', 'array', 'blocks', etc.)
- GeneratedSchemaPathMap module augmentation flows types through
- Conditional FieldConfigFor<T> provides type-appropriate component
  slots per field type (e.g. RowLabel only on array fields,
  Block only on block paths)
- CollectionSlug/GlobalSlug used for collection/global keys
- Admin test configs use hardcoded string literals instead of
  template literal slug variables