Arcp.Otel.md lists span attributes the code never emits

[nficano]

Category: docs Severity: major
Location: docs/projects/Arcp.Otel.md:76-79

What

ArcpTracing.SetCommonAttributes (src/Arcp.Otel/ArcpTracing.cs:82-92) sets only Direction, Type, Id, SessionId, JobId, TraceId, EventSeq. The constants Agent/LeaseCapabilities/LeaseExpiresAt/BudgetRemaining (ArcpDiagnostics.cs:24-30) are defined but never passed to SetTag anywhere in src (verified by grep). The documented table claims four attributes that are never produced.

Evidence

| `arcp.agent`                 | `payload.agent` (on submit / accept)     |
| `arcp.lease.capabilities`    | comma-joined lease keys                  |
| `arcp.lease.expires_at`      | ISO 8601 string (v1.1)                   |
| `arcp.budget.remaining`      | JSON-stringified currency map (v1.1)     |

Proposed fix

Either emit these four attributes in ArcpTracing.SetCommonAttributes, or delete the four unimplemented rows from the table.

Acceptance criteria

• Every attribute listed in the table is actually emitted by ArcpTracing, or the unimplemented rows are removed.

[nficano]

Fixed in #77 (merged).