admin: Implement admin client infrastructure

- Create AdminClient base class with HTTP request handling and
error mapping
- Implement DatasetsClient with register/deploy/list/delete operations
- Implement JobsClient with get/list/wait/stop/delete operations
- Implement SchemaClient for SQL validation and schema inference
- Create DeploymentContext for chainable deployment workflows
- Add exception hierarchy with 30+ typed error classes mapped from
API codes
- Support automatic job polling with configurable timeout

Author: fordN

src/amp/admin/__init__.py

@@ -0,0 +1,100 @@
+"""Admin API client for Amp.
+
+This module provides HTTP client functionality for interacting with the Amp Admin API,
+enabling dataset registration, deployment, manifest generation, and job monitoring.
+
+Example:
+    >>> from amp.admin import AdminClient
+    >>> client = AdminClient('http://localhost:8080')
+    >>> datasets = client.datasets.list_all()
+"""
+
+from .client import AdminClient
+from .datasets import DatasetsClient
+from .deployment import DeploymentContext
+from .errors import (
+    AdminAPIError,
+    CreateProviderError,
+    DatabaseError,
+    DatasetNotFoundError,
+    DeleteLocationError,
+    DeleteProviderError,
+    DependencyValidationError,
+    FileNotFoundError,
+    GetDatasetVersionError,
+    GetFileInfoError,
+    GetManifestError,
+    GetOutputSchemaError,
+    InternalServerError,
+    InvalidManifestError,
+    InvalidPathError,
+    InvalidPayloadError,
+    JobDeleteError,
+    JobNotFoundError,
+    JobsDeleteError,
+    JobStopError,
+    ListAllDatasetsError,
+    ListDatasetVersionsError,
+    ListJobsError,
+    ListLocationFilesError,
+    ListLocationsError,
+    ListProvidersError,
+    LocationNotFoundError,
+    ManifestLinkingError,
+    ManifestNotFoundError,
+    ManifestRegistrationError,
+    ProviderNotFoundError,
+    SchedulerError,
+    StoreError,
+    UnlinkDatasetManifestsError,
+    UnsupportedDatasetKindError,
+    VersionTaggingError,
+)
+from .jobs import JobsClient
+from .schema import SchemaClient
+
+__all__ = [
+    # Core clients
+    'AdminClient',
+    'DatasetsClient',
+    'JobsClient',
+    'SchemaClient',
+    'DeploymentContext',
+    # Exceptions
+    'AdminAPIError',
+    'InvalidPayloadError',
+    'InvalidManifestError',
+    'DatasetNotFoundError',
+    'DependencyValidationError',
+    'ManifestRegistrationError',
+    'ManifestLinkingError',
+    'ManifestNotFoundError',
+    'VersionTaggingError',
+    'UnsupportedDatasetKindError',
+    'StoreError',
+    'UnlinkDatasetManifestsError',
+    'ListAllDatasetsError',
+    'ListDatasetVersionsError',
+    'GetDatasetVersionError',
+    'GetManifestError',
+    'JobNotFoundError',
+    'ListJobsError',
+    'SchedulerError',
+    'JobStopError',
+    'JobDeleteError',
+    'JobsDeleteError',
+    'LocationNotFoundError',
+    'ListLocationsError',
+    'DeleteLocationError',
+    'ListLocationFilesError',
+    'FileNotFoundError',
+    'GetFileInfoError',
+    'ProviderNotFoundError',
+    'CreateProviderError',
+    'ListProvidersError',
+    'DeleteProviderError',
+    'GetOutputSchemaError',
+    'InvalidPathError',
+    'DatabaseError',
+    'InternalServerError',
+]

src/amp/admin/client.py

@@ -0,0 +1,133 @@
+"""Base HTTP client for Amp Admin API.
+
+This module provides the core AdminClient class for communicating
+with the Amp Admin API over HTTP.
+"""
+
+from typing import Optional
+
+import httpx
+
+from .errors import map_error_response
+
+
+class AdminClient:
+    """HTTP client for Amp Admin API.
+
+    Provides access to Admin API endpoints through sub-clients for
+    datasets, jobs, and schema operations.
+
+    Args:
+        base_url: Base URL for Admin API (e.g., 'http://localhost:8080')
+        auth_token: Optional Bearer token for authentication
+
+    Example:
+        >>> client = AdminClient('http://localhost:8080')
+        >>> datasets = client.datasets.list_all()
+    """
+
+    def __init__(self, base_url: str, auth_token: Optional[str] = None):
+        """Initialize Admin API client.
+
+        Args:
+            base_url: Base URL for Admin API (e.g., 'http://localhost:8080')
+            auth_token: Optional Bearer token for authentication
+        """
+        self.base_url = base_url.rstrip('/')
+
+        # Build headers
+        headers = {}
+        if auth_token:
+            headers['Authorization'] = f'Bearer {auth_token}'
+
+        # Create HTTP client
+        self._http = httpx.Client(
+            base_url=self.base_url,
+            headers=headers,
+            timeout=30.0,
+            follow_redirects=True,
+        )
+
+    def _request(
+        self, method: str, path: str, json: Optional[dict] = None, params: Optional[dict] = None, **kwargs
+    ) -> httpx.Response:
+        """Make HTTP request with error handling.
+
+        Args:
+            method: HTTP method (GET, POST, DELETE, etc.)
+            path: API endpoint path (e.g., '/datasets')
+            json: Optional JSON request body
+            params: Optional query parameters
+            **kwargs: Additional arguments passed to httpx.request()
+
+        Returns:
+            HTTP response object
+
+        Raises:
+            AdminAPIError: If the API returns an error response
+        """
+        response = self._http.request(method, path, json=json, params=params, **kwargs)
+
+        # Handle error responses
+        if response.status_code >= 400:
+            try:
+                error_data = response.json()
+                raise map_error_response(response.status_code, error_data)
+            except ValueError:
+                # Response is not JSON, fall back to generic HTTP error
+                response.raise_for_status()
+
+        return response
+
+    @property
+    def datasets(self):
+        """Access datasets client.
+
+        Returns:
+            DatasetsClient for dataset operations
+        """
+        from .datasets import DatasetsClient
+
+        return DatasetsClient(self)
+
+    @property
+    def jobs(self):
+        """Access jobs client.
+
+        Returns:
+            JobsClient for job operations
+        """
+        from .jobs import JobsClient
+
+        return JobsClient(self)
+
+    @property
+    def schema(self):
+        """Access schema client.
+
+        Returns:
+            SchemaClient for schema operations
+        """
+        from .schema import SchemaClient
+
+        return SchemaClient(self)
+
+    def close(self):
+        """Close the HTTP client and release resources.
+
+        Example:
+            >>> client = AdminClient('http://localhost:8080')
+            >>> try:
+            ...     datasets = client.datasets.list_all()
+            ... finally:
+            ...     client.close()
+        """
+        self._http.close()
+
+    def __enter__(self):
+        """Context manager entry."""
+        return self
+
+    def __exit__(self, exc_type, exc_val, exc_tb):
+        """Context manager exit."""
+        self.close()