SIENTIAPDE-1811

Enhance OPC UA communication and metrics tracking

- Updated README.md to include new OPC UA Communication section and detailed metrics for session and write diagnostics.
- Added new metrics in laborious/metrics.py for tracking OPC UA session states and write attempts.
- Refactored OPC activity in laborious/activities/opc.py to handle session errors and improve error reporting.
- Updated e2e tests to cover new scenarios for OPC session/channel errors and reconnect handling.
- Modified .gitignore to include relatorio files and mlruns directory.
- Added ipykernel to requirements-dev.txt for Jupyter notebook support.

e2e/scenarios.md

@@ -495,6 +495,48 @@ These paths do **not** rely on Temporal activity retries for export failures: th
 
 ---
 
+#### Scenario 3.2.4: OPC Session / Channel Bad* (Tier-1)
+**Description**: OPC write fails with a Tier-1 session or channel status (e.g. `BadSessionIdInvalid`) while transport may still appear open on the client
+
+**Input**:
+- Valid prediction and OPC output config
+- Mock or server returning Tier-1 `UaStatusCodeError` on write (no write retry in the same activity)
+
+**Expected Behavior**:
+- `write_opc_data` fails forward for affected tags; background reconnect may be scheduled if `OPC_RECONNECTION_INTERVAL` allows
+- Workflow **completes**
+- PostgreSQL row uses **`prediction_confidence` 14** and comment prefix `OPC UA session/channel error:` (including OPC status name)
+- `opc_write_attempts_total` records `result=BadSessionIdInvalid` (or matching status); no second write attempt in the same activity
+
+**Assertions**:
+- Workflow completes
+- `prediction_confidence = 14`
+- `comments` matches `OPC UA session/channel error:%`
+- Generic OPC error confidence **12** is not used for this case
+
+**Reference**: [docs/opc-communication.md](../docs/opc-communication.md), plan `.cursor/plans/opc_bad_reconnect_ac4c6045.plan.md`
+
+---
+
+#### Scenario 3.2.5: OPC Write Blocked During Reconnect
+**Description**: A write is attempted while the repository is reconnecting (session not ready)
+
+**Input**:
+- Valid prediction
+- Simulated slow reconnect (e.g. delayed `connect`) or concurrent writes where the first triggers reconnect
+
+**Expected Behavior**:
+- Second write (or parallel write) is rejected **immediately** when reconnect is in progress or `_session_ready` is cleared — **without** calling `write_value`
+- No wait/sleep on the write path; no duplicate `connect` from parallel writers (connection lock)
+- `prediction_confidence = 14`, `comments = OPC UA reconnect in progress` (distinguish from Tier-1 `Bad*` via comment prefix in SQL)
+
+**Assertions**:
+- At most one reconnect sequence (`disconnect` + `connect`) for the overlapping window
+- No write retry after failure
+- Tests in `test_opc_repository` (unit) and optional e2e in `test_predictions_batch_format_export.py`
+
+---
+
 #### Scenario 3.2.3: PI Web API Partial Write Error
 **Description**: Two prediction tags attempt to be written to PI Web API, but only one succeeds