feat: add Jarvis agent verification foundation

Add Day 1 agent runtime foundations with task and event schemas, verifier support, capability metadata, graph event tracing, and regression coverage while preserving the direct execution path.

backend/app/agents/verifier.py

@@ -0,0 +1,60 @@
+from __future__ import annotations
+
+from typing import Any
+
+from pydantic import BaseModel, Field
+
+from app.agents.schemas.task import AgentTask, TaskResult, VerificationStatus
+from app.agents.state import AgentState
+
+
+class VerificationVerdict(BaseModel):
+    status: VerificationStatus
+    summary: str | None = None
+    evidence: list[dict[str, Any]] = Field(default_factory=list)
+
+
+def verify_task_result(
+    *,
+    task: AgentTask | dict[str, Any] | None = None,
+    result: TaskResult | dict[str, Any] | None = None,
+    summary: str | None = None,
+    evidence: list[dict[str, Any]] | None = None,
+    status: VerificationStatus | None = None,
+) -> VerificationVerdict:
+    normalized_result = result.model_dump() if isinstance(result, TaskResult) else dict(result or {})
+    normalized_task = task.model_dump() if isinstance(task, AgentTask) else dict(task or {})
+    normalized_summary = summary or normalized_result.get("summary") or normalized_task.get("result_summary")
+    normalized_evidence = list(evidence or normalized_result.get("evidence") or normalized_task.get("evidence") or [])
+
+    if status is not None:
+        return VerificationVerdict(status=status, summary=normalized_summary, evidence=normalized_evidence)
+
+    if normalized_result.get("status") in {"passed", "failed", "skipped"}:
+        inferred_status = normalized_result["status"]
+    elif normalized_result.get("success") is True:
+        inferred_status = "passed"
+    elif normalized_result.get("success") is False:
+        inferred_status = "failed"
+    elif normalized_summary or normalized_evidence:
+        inferred_status = "skipped"
+    else:
+        inferred_status = "failed"
+        normalized_summary = "No verification input available."
+
+    return VerificationVerdict(
+        status=inferred_status,
+        summary=normalized_summary,
+        evidence=normalized_evidence,
+    )
+
+
+def apply_verification_verdict(state: AgentState, verdict: VerificationVerdict) -> AgentState:
+    next_state = dict(state)
+    next_state["verification_status"] = verdict.status
+    next_state["verification_summary"] = verdict.summary
+    next_state["verification_evidence"] = list(verdict.evidence)
+    return AgentState(**next_state)
+
+
+__all__ = ["VerificationVerdict", "apply_verification_verdict", "verify_task_result"]