Allow subscriptions to declare their real bar period

[YadavKapil]

Description

LEAN derives a bar's length from the name of its resolution, so data whose stored period differs from the nominal one is misdescribed. Concretely, 30-minute bars kept in the minute folders are treated as 1-minute bars: FillForwardEnumerator manufactures ~29 synthetic bars per real bar, and every bar is stamped with an end time 29 minutes too early.

This adds an optional barPeriod to SubscriptionDataConfig, surfaced on AddEquity, AddIndex, AddOption, AddIndexOption, AddSecurity and UniverseSettings:

AddEquity("SPY", Resolution.Minute, barPeriod: TimeSpan.FromMinutes(30));

It defaults to null, so the period continues to be derived from the resolution and no existing algorithm changes behaviour. Resolution is deliberately untouched, so data still resolves from the same files and no data needs regenerating.

With the period declared, ShouldFillForward sees a gap equal to the period rather than 30x it, so no synthetic bars are emitted when the data is complete, and genuine gaps are still filled with exactly one bar.

Four latent Resolution-as-duration reads

Four places read Resolution where they mean a duration. They agree today because Increment is a pure function of Resolution, so each change is provably equivalent for any subscription that does not declare a period, and the PR includes tests asserting that equivalence across all five resolutions.

Location	Issue
SubscriptionCollection	Derived the fill-forward cadence from the resolution enum, which would reinstate the synthetic bars
FillModel.ShouldWaitForFreshData	Tested Resolution.Hour/Daily to decide whether a resting order fills at the bar open rather than its close. Now Increment > Time.OneMinute, which selects exactly Hour and Daily. Without this, a declared 30-minute bar would fill at the close of the following bar
FillModel stale threshold	Sized via GetHighestResolution().ToTimeSpan(). Added GetHighestResolutionSpan(), taking the minimum Increment
CreateConsolidator	Compared a TimeSpan against Increment and a Resolution against Resolution in one expression. Both now compare durations

The consolidator change also fixes a pre-existing bug: against coarser-than-nominal data, SMA(symbol, 20, Resolution.Minute) evaluated Minute < Minute as false, skipped the guard, matched the identity branch and silently returned the coarser bars labelled as minute bars. It now throws.

Equals/GetHashCode include the declared period so configs differing only by it are not deduplicated, and the copy constructor drops it when the resolution changes, since it described the previous resolution.

Testing

New fixture Tests/Common/Data/SubscriptionDataConfigBarPeriodTests.cs (23 tests) covers the equivalence proofs, config identity, copy-constructor inheritance, and validation. Two new FillForwardEnumeratorTests assert that a declared period emits zero synthetic bars with correct end times, while a genuine gap is still filled.

Suites run green in quantconnect/lean:foundation:

Filter	Result
SubscriptionDataConfigBarPeriodTests	23 passed
FillForwardEnumeratorTests, SubscriptionCollectionTests, SubscriptionDataConfigTests	315 passed
Fills, FillModel	544 passed, 2 skipped
Consolidator, HistoryRequest, UniverseSettings	669 passed

Full solution builds clean on net10.0.