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.AbCip/findings.md

@@ -7,7 +7,7 @@
 | Review date | 2026-06-19 |
 | Commit reviewed | `7286d320` |
 | Status | Reviewed |
-| Open findings | 1 |
+| Open findings | 0 |
 
 ## Checklist coverage
 
@@ -337,7 +337,7 @@ flag and the legacy `ElementCount > 1` paths opt out). Full suite green (303 tes
 | Severity | Low |
 | Category | Documentation & comments |
 | Location | `AbCipAlarmProjection.cs:173-185` (`Tick`) |
-| Status | Open |
+| Status | Resolved |
 
 **Description:** `AbCipAlarmProjection.Tick` gates each node on the `InFaulted` snapshot's
 `StatusCode` (`if (inFaultedDv.StatusCode != Good) continue;`) but reads the `Severity`
@@ -357,6 +357,12 @@ severity read is Bad, or add an XML/inline comment on `Tick` stating that severi
 decision (what severity to surface when it is genuinely unknown) rather than a mechanical fix,
 and the impact is negligible given the single-batch read shape.
 
+**Resolution:** Resolved 2026-06-20 — added an inline comment on the `severity` read line in
+`Tick` documenting that `severityDv.StatusCode` is not checked, that a Bad Severity read yields
+`ToInt(null)=0` → `MapSeverity` buckets as Low, and that this is acceptable because InFaulted
+and Severity are members of the same ALMD UDT read in one batch (a Good InFaulted almost always
+implies a Good Severity). No behaviour change.
+
 ### Driver.AbCip-018
 
 | Field | Value |