fix(code-review): resolve Batch 2 open findings (AbCip, AbLegacy, Galaxy, FOCAS)

- Driver.AbCip.Contracts-001: parse 'writable' from TagConfig JSON (default true) instead of hardcoding
- Driver.AbCip.Contracts-002/-003: Dt type comment; drop dead [Display]/[Range] annotations
- Driver.AbCip.Contracts-004: dedicated AbCipEquipmentTagParser test class (+15)
- Driver.AbCip-017: document Tick severity Low-fallback on Bad severity read
- Driver.AbLegacy.Contracts-002/-003/-004: isArray-scalar remarks (+tests), MaxTagBytes/ForFamily docs
- Driver.Galaxy.Browser-003 + Driver.Galaxy.Contracts-003: extract ResolveApiKey -> GalaxySecretRef (dedup)
- Driver.Galaxy-019: cache buffered-interval only on Ok + ILogger warnings + ClassifyIntervalReply (+tests)
- Driver.FOCAS.Contracts-002: thread WriteIdempotent through DiscoverAsync (+test)

code-reviews/Driver.FOCAS.Contracts/findings.md

@@ -11,7 +11,7 @@
 | Review date | 2026-06-19 |
 | Commit reviewed | `7286d320` |
 | Status | Reviewed |
-| Open findings | 1 |
+| Open findings | 0 |
 
 ## Checklist coverage
 
@@ -61,13 +61,13 @@ a category produced nothing rather than leaving it blank.
 | Severity | Low |
 | Category | Design-document adherence |
 | Location | `src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.FOCAS.Contracts/FocasDriverOptions.cs:139-145` |
-| Status | Open |
+| Status | Resolved |
 
 **Description:** `FocasTagDefinition` carries a `WriteIdempotent` field (default `false`) that the FOCAS driver never reads anywhere — neither in `DiscoverAsync`, `ReadAsync`, nor `WriteAsync`. `DiscoverAsync` always passes `WriteIdempotent: false` to `DriverAttributeInfo` (hardcoded), so the field has no runtime effect. `docs/drivers/FOCAS.md` does not mention `WriteIdempotent` in its configuration tables, making its purpose undiscoverable to operators.
 
 **Recommendation:** Either (a) thread `FocasTagDefinition.WriteIdempotent` through to `DriverAttributeInfo` in `DiscoverAsync` so the field has runtime effect and matches the pattern of other drivers, or (b) remove it from the record and the `FocasDriverConfigDto` wire DTO. Option (a) is the safer fix and matches the design of Modbus and other drivers. This is deferred because the fix touches `FocasDriver.DiscoverAsync` outside this module and requires a driver-level test change.
 
-**Resolution:** _(empty until closed)_
+**Resolution:** Fixed (option a). In `FocasDriver.DiscoverAsync` the hardcoded `WriteIdempotent: false` was replaced with `tag.WriteIdempotent` so each user-authored tag's per-tag value is now threaded through to `DriverAttributeInfo`. The `<param name="WriteIdempotent">` doc on `FocasTagDefinition` was updated to state it is now threaded through `DiscoverAsync` to `DriverAttributeInfo`. A new test `DiscoverAsync_surfaces_WriteIdempotent_from_tag_definition` was added to `FocasDriverMediumFindingsTests` asserting both the `true` and `false` cases surface correctly. The full `Driver.FOCAS.Tests` suite (including `FocasPmcBitRmwTests` and `FocasReadWriteTests` write tests) passes.
 
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