Fuaran.Core.DataFrame 0.28.0

Fuaran.Core.Column.Ops — a columnar op-algebra over Fuaran.Core.Column's Table (SetCell / SetColumn / InsertColumn / RemoveColumn / AppendRows / ApplyTransform) with a total apply / canApply, a partial invert (undo/redo), a structural Diff, a canonical wire codec, and a Fuaran.Core.OpStream StreamWitness — so table edits become an append-only, hash-chained, replayable, tamper-evident stream (the columnar analogue of the tree op-stream). No base type, no new witness field (the op DU is self-contained over Table; OpStream stays generic over its (apply, encode, decode) witness). FSharp.Core only, Fable-clean.

Drift detector for Fuaran op-apply telemetry. Computes per-OpKind aggregate metrics (success rate, p50/p95 latency, top decoder-rejection reasons, top NodeNotFound NodeIds) and flags week-on-week success-rate regressions exceeding an operator-tunable threshold (default 10pp). Also ships a deterministic StyleFlag drift detector (Phase 151) — the resolved-style twin that diffs declared-invariant flag sets across two windows of StyleObservation to surface newly-introduced / cleared visual-legibility violations, severity-weighted by the ThemeManifest's invariant weights (semantic visual regression, no pixels, CI-gateable). Manual-run console tool for now (`dotnet run --project src/Fuaran.UI.Telemetry.Drift`); cron-friendly later when an operator-decided threshold is wired into a scheduled job. Companion to Fuaran.UI.Telemetry.Abstractions. Apache-2.0 licensed.

Fuaran.Core.DataFrame.Conformance — the law families over the dataframe layer, beside the Fuaran.Core.Conformance kit they extend: transform parity against the DataFrame reference evaluator, the columnar op-algebra and op-stream (ColumnOps), incremental evaluation (evalFrom and the IncrementalDelta equivalence family), params and slot params, the static output-schema walk, the pinned evaluation clock, and aggregate-versus-GroupBy parity. The families ship in module DataFrameConformance; the pre-split Conformance.* spellings forward to them (marked for removal in Phase 258). FSharp.Core only, Fable-clean.

Fuaran.Core.DataFrame.CSharp (Phase 257) — the dataframe half of the C#-shaped facade: ColExpr (Expr, CaseArm), Transform (Step, Pipeline and the named step specs), the slot types and the dataframe vocabularies (BinaryOperator, ScalarFunction, JoinMode, SortOrder, ClockGrain), in the Fuaran.Core.CSharp namespace they shipped in until Phase 257. Construction is factory methods, reading is Match / Switch, and nothing but the declared ToCore / FromCore bridge mentions an F# option, list, function or union type. Built over Fuaran.Core.CSharp, whose column and wire types (CellValue, TableValue, SourceValue, ColumnKind, AggregateFunction, JsonValue) it reads. .NET-only: not part of the Fable-clean set (a C# assembly is not Fable-compiled).