docs: apply fleet-template (16-artifact scaffold)

Adds missing standard artifacts:
- README.md (if missing)
- AGENTS.md (AI agent contract)
- PLAN.md (current sprint)
- STATUS.md (where we are)
- DEVELOPMENT.md (dev workflow)
- DEPLOYMENT.md (deploy procedure)
- TESTING.md (test strategy)
- DECISIONS.md (ADR index + templates)
- .github/CODEOWNERS
- .github/workflows/ci.yml

Preserves all existing artifacts.

Refs: RugMunchMedia/fleet-template

errors.py

@@ -0,0 +1,49 @@
+"""Pry — typed error hierarchy.
+Every API error flows through here for consistent JSON responses."""
+
+from typing import Any
+
+
+class PryError(Exception):
+    """Base error for all Pry exceptions."""
+
+    status_code: int = 500
+    code: str = "internal_error"
+    message: str = "An unexpected error occurred"
+    details: dict[str, Any] | None = None
+
+    def __init__(self, message: str | None = None, details: dict[str, Any] | None = None) -> None:
+        self.message = message or self.message
+        self.details = details
+        super().__init__(self.message)
+
+    def to_dict(self) -> dict[str, Any]:
+        d: dict[str, Any] = {"code": self.code, "message": self.message}
+        if self.details:
+            d["details"] = self.details
+        return d
+
+
+class NotFoundError(PryError):
+    status_code = 404
+    code = "not_found"
+
+
+class RateLimitError(PryError):
+    status_code = 429
+    code = "rate_limit_exceeded"
+
+
+class ScrapeError(PryError):
+    status_code = 422
+    code = "scrape_failed"
+
+
+class InvalidRequestError(PryError):
+    status_code = 400
+    code = "invalid_request"
+
+
+class ExternalServiceError(PryError):
+    status_code = 502
+    code = "external_service_error"