[MarcelT87]

Summary

Apply the same bounded structured-input handling used by bundle verification to local state, context, profile and system-identity files.

The public bundle path was already hardened in #27. Local beginner-facing files could still surface a raw Python RecursionError or reach recursive processing when given pathologically nested data.

Changes

• centralize the existing structure limits in a small shared helper;
• preserve the current bundle limits and behavior;
• apply the same limits to:
  • local evidence state JSON;
  • local context metadata JSON;
  • explicit/local YAML profiles;
  • local system identity JSON;
• translate JSON/YAML recursion failures into the existing domain errors:
  • StateError;
  • ContextError;
  • ProfileError;
  • SystemIdentityError.

Current limits remain:

• maximum nesting depth: 64;
• maximum traversed structure size: 1,000,000 nodes;
• repeated/cyclic container references are rejected.

Tests

Adds regression coverage for:

• deeply nested local state;
• deeply nested local context metadata;
• deeply nested local profile;
• cyclic YAML alias profile;
• deeply nested local system identity.

Existing bundle hardening tests continue to exercise the same limits through the shared helper.

Scope

Robustness and beginner-facing error handling only.

No eBUS parser, transport framing, Evidence semantics, profile content, bundle schema, submission policy or heating-system behavior changes.