chore(release): 0.0.3

Squash-merge lib-standardisation: adopt repo standards across packaging,
tooling, docs, and CI.

- standardize pyproject.toml (canonical packaging, lint config, extras, GSDFC pydoclint)
- add py.typed marker, modernize type hints and Google-style docstrings
- nest generated docs under docs/lib and docs/mcp; add hand-written wiki
- adopt standard Type A PyPI CI pipeline (tag==version guard + quality gate)
- promote generated CHANGELOG.md; bump version to 0.0.3

docs/mcp/modules/mail_intake.config.json

@@ -0,0 +1,53 @@
+{
+  "module": "mail_intake.config",
+  "content": {
+    "path": "mail_intake.config",
+    "docstring": "# Summary\n\nGlobal configuration models for Mail Intake.\n\nThis module defines the **top-level configuration object** used to control\nmail ingestion behavior across adapters, authentication providers, and\ningestion workflows.\n\nConfiguration is intentionally explicit, immutable, and free of implicit\nenvironment reads to ensure predictability and testability.",
+    "objects": {
+      "MailIntakeConfig": {
+        "name": "MailIntakeConfig",
+        "kind": "class",
+        "path": "mail_intake.config.MailIntakeConfig",
+        "signature": "MailIntakeConfig(provider: str = ..., user_id: str = ..., readonly: bool = ..., credentials_path: str | None = ..., token_path: str | None = ...)",
+        "docstring": "Global configuration for `mail-intake`.\n\nNotes:\n    **Guarantees:**\n\n        - This configuration is intentionally explicit and immutable.\n        - No implicit environment reads or global state.\n        - Explicit configuration over implicit defaults.\n        - No direct environment or filesystem access.\n        - This model is safe to pass across layers and suitable for\n          serialization.",
+        "members": {
+          "provider": {
+            "name": "provider",
+            "kind": "attribute",
+            "path": "mail_intake.config.MailIntakeConfig.provider",
+            "signature": null,
+            "docstring": "Identifier of the mail provider to use (e.g., ``\"gmail\"``)."
+          },
+          "user_id": {
+            "name": "user_id",
+            "kind": "attribute",
+            "path": "mail_intake.config.MailIntakeConfig.user_id",
+            "signature": null,
+            "docstring": "Provider-specific user identifier. Defaults to the authenticated user."
+          },
+          "readonly": {
+            "name": "readonly",
+            "kind": "attribute",
+            "path": "mail_intake.config.MailIntakeConfig.readonly",
+            "signature": null,
+            "docstring": "Whether ingestion should operate in read-only mode."
+          },
+          "credentials_path": {
+            "name": "credentials_path",
+            "kind": "attribute",
+            "path": "mail_intake.config.MailIntakeConfig.credentials_path",
+            "signature": null,
+            "docstring": "Optional path to provider credentials configuration."
+          },
+          "token_path": {
+            "name": "token_path",
+            "kind": "attribute",
+            "path": "mail_intake.config.MailIntakeConfig.token_path",
+            "signature": null,
+            "docstring": "Optional path to persisted authentication tokens."
+          }
+        }
+      }
+    }
+  }
+}