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.AbLegacy.Contracts/findings.md

@@ -11,7 +11,7 @@
 | Review date | 2026-06-19 |
 | Commit reviewed | `a19b0f86` |
 | Status | Reviewed |
-| Open findings | 3 |
+| Open findings | 0 |
 
 ## Checklist coverage
 
@@ -69,7 +69,7 @@ verified by build (no test project in this module).
 | Severity | Low |
 | Category | Documentation & comments |
 | Location | `src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Contracts/AbLegacyEquipmentTagParser.cs:15` |
-| Status | Open |
+| Status | Resolved |
 
 **Description:** `AbLegacyEquipmentTagParser.TryParse` has an undocumented edge case: when
 `isArray` is the JSON literal `true` but `arrayLength` is absent, zero, or negative,
@@ -85,7 +85,13 @@ without a valid positive `arrayLength` silently produces a scalar (null `ArrayLe
 Optionally add a unit test to `AbLegacyEquipmentTagTests` covering
 `isArray:true, arrayLength:0/absent -> null` for regression protection.
 
-**Resolution:** _(empty until closed)_
+**Resolution:** Resolved 2026-06-20. Added a `<remarks>` block to `TryParse` in
+`AbLegacyEquipmentTagParser.cs` documenting that `isArray:true` without a valid positive
+`arrayLength` silently produces a scalar (`ArrayLength` is `null`), referencing the
+in-source review C-2 rationale. Added three regression unit tests to
+`AbLegacyEquipmentTagTests`: `IsArray_true_with_arrayLength_zero_produces_scalar`,
+`IsArray_true_with_no_arrayLength_produces_scalar`, and
+`IsArray_true_with_negative_arrayLength_produces_scalar`. Suite: 199 passed, 0 failed.
 
 ---
 
@@ -96,7 +102,7 @@ Optionally add a unit test to `AbLegacyEquipmentTagTests` covering
 | Severity | Low |
 | Category | OtOpcUa conventions |
 | Location | `src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Contracts/AbLegacyPlcFamilyProfile.cs:10` |
-| Status | Open |
+| Status | Resolved |
 
 **Description:** `AbLegacyPlcFamilyProfile.MaxTagBytes` is a record constructor parameter
 populated with distinct values per family (240/232/240/240), but a global search finds zero
@@ -111,7 +117,11 @@ produce off-by-one sizing. If reserved for future clamping, the intent is undocu
 clamping and is not currently enforced, or (b) remove the field and its four initialisers
 in a dedicated cleanup PR (signature change is out of scope for this review).
 
-**Resolution:** _(empty until closed)_
+**Resolution:** Resolved 2026-06-20. Applied option (a): added XML doc on the `MaxTagBytes`
+constructor parameter in `AbLegacyPlcFamilyProfile.cs` noting it is reserved for future
+array-length clamping, is NOT currently enforced anywhere in the driver, and that the values
+are approximate PCCC packet payload caps (not libplctag fragment limits). Field and
+initialisers unchanged.
 
 ---
 
@@ -122,7 +132,7 @@ in a dedicated cleanup PR (signature change is out of scope for this review).
 | Severity | Low |
 | Category | Code organization & conventions |
 | Location | `src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbLegacy.Contracts/AbLegacyPlcFamilyProfile.cs:22` |
-| Status | Open |
+| Status | Resolved |
 
 **Description:** `AbLegacyPlcFamilyProfile.ForFamily` has a catch-all arm `_ => Slc500`
 that silently returns the SLC 500 profile for any unrecognised `AbLegacyPlcFamily` value
@@ -139,4 +149,8 @@ added), or (b) replace `_ => Slc500` with
 `_ => throw new ArgumentOutOfRangeException(nameof(family), family, null)` and apply it
 in a cleanup PR. Semantic change -- defer.
 
-**Resolution:** _(empty until closed)_
+**Resolution:** Resolved 2026-06-20. Applied option (a): added a `<remarks>` block to the
+`ForFamily` XML doc in `AbLegacyPlcFamilyProfile.cs` documenting that any unrecognised
+`family` value silently returns the `Slc500` profile, and noting this is intentional for
+forward-compatibility with configs authored before a new family enum member is added. The
+switch body is unchanged.