feat: Stage 1 — integration foundation (base classes, manifest, registry)

Add the integrations package with:
- IntegrationBase ABC and MarkdownIntegration base class
- IntegrationOption dataclass for per-integration CLI options
- IntegrationManifest with SHA-256 hash-tracked install/uninstall
- INTEGRATION_REGISTRY (empty, populated in later stages)
- 34 tests at 98% coverage

Purely additive — no existing code modified.

Part of #1924

Author: mnriem

src/specify_cli/integrations/__init__.py

@@ -0,0 +1,34 @@
+"""Integration registry for AI coding assistants.
+
+Each integration is a self-contained subpackage that handles setup/teardown
+for a specific AI assistant (Copilot, Claude, Gemini, etc.).
+"""
+
+from __future__ import annotations
+
+from typing import TYPE_CHECKING
+
+if TYPE_CHECKING:
+    from .base import IntegrationBase
+
+# Maps integration key → IntegrationBase instance.
+# Populated by later stages as integrations are migrated.
+INTEGRATION_REGISTRY: dict[str, IntegrationBase] = {}
+
+
+def _register(integration: IntegrationBase) -> None:
+    """Register an integration instance in the global registry.
+
+    Raises ``ValueError`` for falsy keys and ``KeyError`` for duplicates.
+    """
+    key = integration.key
+    if not key:
+        raise ValueError("Cannot register integration with an empty key.")
+    if key in INTEGRATION_REGISTRY:
+        raise KeyError(f"Integration with key {key!r} is already registered.")
+    INTEGRATION_REGISTRY[key] = integration
+
+
+def get_integration(key: str) -> IntegrationBase | None:
+    """Return the integration for *key*, or ``None`` if not registered."""
+    return INTEGRATION_REGISTRY.get(key)

src/specify_cli/integrations/base.py

@@ -0,0 +1,201 @@
+"""Base classes for AI-assistant integrations.
+
+Provides:
+- ``IntegrationOption`` — declares a CLI option an integration accepts.
+- ``IntegrationBase`` — abstract base every integration must implement.
+- ``MarkdownIntegration`` — concrete base for standard Markdown-format
+  integrations (the common case — subclass, set three class attrs, done).
+"""
+
+from __future__ import annotations
+
+import shutil
+from abc import ABC
+from dataclasses import dataclass
+from pathlib import Path
+from typing import Any
+
+
+# ---------------------------------------------------------------------------
+# IntegrationOption
+# ---------------------------------------------------------------------------
+
+@dataclass(frozen=True)
+class IntegrationOption:
+    """Declares an option that an integration accepts via ``--integration-options``.
+
+    Attributes:
+        name:      The flag name (e.g. ``"--commands-dir"``).
+        is_flag:   ``True`` for boolean flags (``--skills``).
+        required:  ``True`` if the option must be supplied.
+        default:   Default value when not supplied (``None`` → no default).
+        help:      One-line description shown in ``specify integrate info``.
+    """
+
+    name: str
+    is_flag: bool = False
+    required: bool = False
+    default: Any = None
+    help: str = ""
+
+
+# ---------------------------------------------------------------------------
+# IntegrationBase — abstract base class
+# ---------------------------------------------------------------------------
+
+class IntegrationBase(ABC):
+    """Abstract base class every integration must implement.
+
+    Subclasses must set the following class-level attributes:
+
+    * ``key``              — unique identifier, matches actual CLI tool name
+    * ``config``           — dict compatible with ``AGENT_CONFIG`` entries
+    * ``registrar_config`` — dict compatible with ``CommandRegistrar.AGENT_CONFIGS``
+
+    And may optionally set:
+
+    * ``context_file``     — path (relative to project root) of the agent
+                             context/instructions file (e.g. ``"CLAUDE.md"``)
+    """
+
+    # -- Must be set by every subclass ------------------------------------
+
+    key: str = ""
+    """Unique integration key — should match the actual CLI tool name."""
+
+    config: dict[str, Any] | None = None
+    """Metadata dict matching the ``AGENT_CONFIG`` shape."""
+
+    registrar_config: dict[str, Any] | None = None
+    """Registration dict matching ``CommandRegistrar.AGENT_CONFIGS`` shape."""
+
+    # -- Optional ---------------------------------------------------------
+
+    context_file: str | None = None
+    """Relative path to the agent context file (e.g. ``CLAUDE.md``)."""
+
+    # -- Public API -------------------------------------------------------
+
+    @classmethod
+    def options(cls) -> list[IntegrationOption]:
+        """Return options this integration accepts. Default: none."""
+        return []
+
+    def templates_dir(self) -> Path:
+        """Return the path to this integration's bundled templates.
+
+        By convention, templates live in a ``templates/`` subdirectory next
+        to the integration's ``__init__.py``.
+        """
+        import inspect
+
+        module_file = inspect.getfile(type(self))
+        return Path(module_file).resolve().parent / "templates"
+
+    def setup(
+        self,
+        project_root: Path,
+        manifest: Any,
+        parsed_options: dict[str, Any] | None = None,
+        **opts: Any,
+    ) -> list[Path]:
+        """Install integration files into *project_root*.
+
+        Returns the list of files created.  The default implementation
+        copies every file from ``templates_dir()`` into the commands
+        directory derived from ``config``, recording each in *manifest*.
+        """
+        created: list[Path] = []
+        tpl_dir = self.templates_dir()
+        if not tpl_dir.is_dir():
+            return created
+
+        if not self.config:
+            return created
+        folder = self.config.get("folder")
+        if not folder:
+            return created
+
+        project_root_resolved = project_root.resolve()
+        subdir = self.config.get("commands_subdir", "commands")
+        dest = (project_root / folder / subdir).resolve()
+        # Ensure destination stays within the project root
+        try:
+            dest.relative_to(project_root_resolved)
+        except ValueError as exc:
+            raise ValueError(
+                f"Integration destination {dest} escapes "
+                f"project root {project_root_resolved}"
+            ) from exc
+
+        dest.mkdir(parents=True, exist_ok=True)
+
+        for src_file in sorted(tpl_dir.iterdir()):
+            if src_file.is_file():
+                dst_file = (dest / src_file.name).resolve()
+                rel = dst_file.relative_to(project_root_resolved)
+                shutil.copy2(src_file, dst_file)
+                manifest.record_existing(rel)
+                created.append(dst_file)
+
+        return created
+
+    def teardown(
+        self,
+        project_root: Path,
+        manifest: Any,
+        *,
+        force: bool = False,
+    ) -> tuple[list[Path], list[Path]]:
+        """Uninstall integration files from *project_root*.
+
+        Delegates to ``manifest.uninstall()`` which only removes files
+        whose hash still matches the recorded value (unless *force*).
+
+        Returns ``(removed, skipped)`` file lists.
+        """
+        return manifest.uninstall(project_root, force=force)
+
+    # -- Convenience helpers for subclasses -------------------------------
+
+    def install(
+        self,
+        project_root: Path,
+        manifest: Any,
+        parsed_options: dict[str, Any] | None = None,
+        **opts: Any,
+    ) -> list[Path]:
+        """High-level install — calls ``setup()`` and returns created files."""
+        return self.setup(
+            project_root, manifest, parsed_options=parsed_options, **opts
+        )
+
+    def uninstall(
+        self,
+        project_root: Path,
+        manifest: Any,
+        *,
+        force: bool = False,
+    ) -> tuple[list[Path], list[Path]]:
+        """High-level uninstall — calls ``teardown()``."""
+        return self.teardown(project_root, manifest, force=force)
+
+
+# ---------------------------------------------------------------------------
+# MarkdownIntegration — covers ~20 standard agents
+# ---------------------------------------------------------------------------
+
+class MarkdownIntegration(IntegrationBase):
+    """Concrete base for integrations that use standard Markdown commands.
+
+    Subclasses only need to set ``key``, ``config``, ``registrar_config``
+    (and optionally ``context_file``).  Everything else is inherited.
+
+    The default ``setup()`` from ``IntegrationBase`` copies templates
+    into the agent's commands directory — which is correct for the
+    standard Markdown case.
+    """
+
+    # MarkdownIntegration inherits IntegrationBase.setup() as-is.
+    # Future stages may add markdown-specific path rewriting here.
+    pass