Add calendarDateRangePickerBuilder to preserve the calendar delegate on Flutter 3.32, whose showDateRangePicker omits it when creating the dialog. Keep selected Persian/Hijri range endpoints in their calendar types while preserving localization, text direction, and dialog options.

Remove internal src/shared forwarding libraries; use calendar helpers and shared implementation utilities from general_datetime_core directly.

Remove the remaining internal chronology forwarding libraries from src/. Material delegates and localizations import the core public library directly; general_datetime.dart continues to re-export the core public API.

Remove the unused scheduling package. Keep named-zone conversion and explicit DST policies in the calendar demo, which depends directly on timezone.

Add rangePickerDelegate adapters for Persian and Umm al-Qura Material range pickers at finite chronology bounds. Empty-cell highlight and keyboard probes use native comparison dates; selectable dates retain their calendar types and supported bounds.

Add the common CalendarSystem contract and immutable built-in registry, strict field construction, supported bounds, and chronology metadata.

Add immutable CalendarDate, explicit day/month/year arithmetic policies, half-open date ranges, and calendar-aware week rules in the Dart core.

Add a separate four-view Flutter calendar demo with named-zone presentation and explicit DST policies.

Resolve published cores in CI; add minimum/current SDK and timezone jobs, JavaScript/Wasm coverage, and Android/iOS smoke workflows. Platform execution remains a release gate; local verification does not establish device support.

Extract chronology, conversion, field utilities, and serialization into general_datetime_core 1.0.0, usable with the Dart SDK alone. Retain the existing Flutter imports as re-exports of the same types and keep picker delegates/default Material localizations in this wrapper. Resolve the published core through general_datetime_core ^1.0.0 without local overrides.

Define secondsSinceEpoch as the containing Unix second, rounded down directly from microseconds in both calendars. Negative fractional instants now use consistent floor rounding; -1 microsecond becomes -1 second and -1000001 microseconds becomes -2 seconds. UTC/local mode does not affect it.

Prevent constructor/copyWith arithmetic from wrapping extreme month, day, and clock components into valid dates. Exact normalization checks supported bounds before narrowing; ordinary normalization, cancellation, microseconds, UTC/local mode, and maximum-date sentinels remain supported.

Added version-1 JSON storage contracts: CalendarInstant serializes exact native Gregorian UTC timestamps with calendar and optional zone metadata; CalendarDateRecord stores validated calendar/year/month/day fields without an implied instant. Added Unicode calendar identifiers, strict decoders, microsecond-preserving round trips, and storage warnings on calendar ISO output.

Persian/Hijri calendar delegates now reject incompatible runtime date types with ArgumentError across field operations, ranges, nullable comparisons, formatting, and non-null localization parser results. Callers must explicitly convert Gregorian/other-calendar instants. Added 38 shared regression tests including Material picker constructor validation and localization forwarding.

Added CalendarDateUtils.copyWith, dateOnly, and toGregorian as explicit calendar-field and native-instant boundaries for DateTime-typed values. Field operations preserve Persian/Hijri types, precision, and UTC/local mode; unsupported calendar interfaces fail explicitly. Documented the upstream DateTime.copyWith/DateUtils limitation and added shared regressions.

Breaking: replaces the published 2.1.0 chronology and native-instant contracts with the corrected implementations described below. Unsupported calendar dates now fail explicitly. The companion formatter wrapper is general_date_format 3.0.0; both pure Dart cores remain at 1.0.0.

Added shared critical suites for both calendars: independent seeded normalization, precision/epoch boundaries, adversarial parsing, DST, calendar interoperability, and picker validation/navigation/localization isolation.

Added exhaustive compact parsing checks over all reference months and a three-time-zone CI matrix with explicit DST assertions.

Fixed oversized epoch seconds/milliseconds wrapping into dates near 1970 in both calendars, with regressions for positive and negative 64-bit inputs.

Aligned Hijri calculations, data-coverage APIs, Material localizations, delegates, scoped picker examples, and tests with the Persian structure.

Added customized Hijri formatting/parsing and input-picker coverage, and corrected the Hijri localization's expansion-state hints.

Fixed Hijri parsing to apply numeric time-zone offsets before validating supported endpoints, retaining microsecond precision.

Cross-checked all 3,612 Umm al-Qura months with ICU 78.3 and Java/OpenJDK 21; replaced incompatible hijri 3.0.1 comparisons with primary-source regressions.

Extended Persian support to SH -61 through 3177 (Gregorian 0560-03-20 through 3799-03-19), retaining published data for SH 1206–1498 and using Borkowski's finite break-year model elsewhere.

Exposed official-data bounds and coverage separately from calculation bounds.

Added signed-year formatting, expanded boundary tests, and exhaustive conversion checks over the extended interval.

Replaced the mixed Persian leap algorithms with a finite official data model sourced from the University of Tehran Calendar Center for SH 1206–1498.

Rebuilt Persian conversion, normalization, parsing, UTC/local handling, epoch factories, arithmetic, equality, hashing, and copyWith around the true native DateTime instant.

Made dates outside the finite Persian calculation range fail explicitly instead of extrapolating a 33-year or 2820-year cycle.

Restored PersianCalendarDelegate to use the current Material localizations for month names, date formatting, parsing, and input help.

Added official-source fixtures and exhaustive Persian calendar, boundary, precision, parsing, delegate, and widget tests.

Replaced the approximate tabular Hijri implementation with the official Unicode ICU/OpenJDK Umm al-Qura month data for AH 1300 through AH 1600.

Rebuilt Hijri conversion, normalization, parsing, UTC/local handling, epoch factories, arithmetic, equality, and copyWith around the true native DateTime instant.

Made unsupported Umm al-Qura dates fail explicitly instead of silently extrapolating another Islamic calendar.

Made HijriCalendarDelegate use the current Material localizations for month names, date formatting, parsing, and input help, like the Persian delegate.

Added exhaustive calendar, boundary, precision, parsing, delegate, and widget tests, independently cross-validated with ICU and OpenJDK.

Raised the declared Flutter minimum to 3.32.0, where CalendarDelegate is available on the stable channel.