Implement DNI, EI Interface, and Damage Interrupt Circuit support

[HammerGS]

Summary

Adds core support loading and improvements to validating for three cockpit modification equipment types: DNI Cockpit Modification (IS, Advanced), Enhanced Imaging (EI) Interface (Clan, Experimental), and Damage Interrupt Circuit (IS, Experimental). Also adds game year validation support for equipment availability.

Requires: MegaMekLab PR Implement-DNI-EI-DIC-UI for full UI functionality.

Changes

1. Add equipment definitions with correct tech levels (DNI=Advanced, DIC=Experimental)
2. Add BLK file save/load for slotless (LOC_NONE) equipment across all unit types
3. Fix Unit Viewer to display cockpit modifications for non-Mek units
4. Add game year support in ITechManager.isLegal() for equipment availability
5. Add game year support in TestEntity.hasIncorrectIntroYear() for validation
6. Mark DNI and EI as retrofittable equipment (skipped in intro year validation per IO p.69)

Files Changed

• MiscType.java - Tech level fixes for DNI and DIC
• ITechManager.java - Game year support in isLegal()
• TestEntity.java - Game year field and validation support
• BLKFile.java - Slotless equipment save/load methods
• BLK*File.java (10 files) - Load slotless equipment for each unit type
• ReadoutUtils.java - Show cockpit mods in Unit Viewer
• *TROView.java (4 files) - TRO display for cockpit mods
• CockpitModificationTest.java - Unit tests for save/load
• TestEntityGameYearValidationTest.java - Unit tests for game year validation

Testing

• Unit Tests: 17 tests covering save/load and game year validation (all passing)
• Manual Testing: Verified on Mek, Combat Vehicle, Conventional Fighter, Aerospace Fighter, Support Vehicle (Ground/VTOL), Battle Armor
  (IS/Clan)
• Game Year Validation: Tested EI (intro 3040) and DNI (intro 3052) with game years before/after intro dates

[Copilot]

Pull request overview

This PR adds support for DNI Cockpit Modifications, EI Interface, and Damage Interrupt Circuit across save/load, validation, and unit readouts, and wires intro-date checks to game-year–based availability.

Changes:

• Marks DNI and DIC with correct static tech levels and treats DNI/EI as retrofittable in intro-year validation logic.
• Extends BLK save/load to persist slotless equipment (LOC_NONE) across multiple unit types, and updates viewer/TRO templates to show cockpit mods on non-‘Mek units.
• Introduces explicit game-year handling in ITechManager.isLegal() and TestEntity.hasIncorrectIntroYear(), with new unit tests covering save/load and game-year validation.

Reviewed changes

Copilot reviewed 20 out of 20 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
megamek/src/megamek/common/equipment/MiscType.java	Sets static tech levels for DNI (Advanced) and DIC (Experimental) to match their intended rules levels.
megamek/src/megamek/common/interfaces/ITechManager.java	Changes isLegal to use getGameYear() for intro/extinction checks and tech-era lookup, aligning legality with configured game year.
megamek/src/megamek/common/verifier/TestEntity.java	Adds a gameYear field with getter/setter and updates hasIncorrectIntroYear to use either the explicit game year or Entity.getTechLevelYear(), and to skip both DNI and EI as retrofittable.
megamek/src/megamek/common/loaders/BLKFile.java	Introduces BLK_SLOTLESS_EQUIPMENT tag plus loadSlotlessEquipment and updates getBlock to persist/load slotless equipment like cockpit mods.
megamek/src/megamek/common/loaders/BLKVTOLFile.java	Calls loadSlotlessEquipment so VTOL BLKs restore slotless cockpit mods.
megamek/src/megamek/common/loaders/BLKTankFile.java	Calls loadSlotlessEquipment so combat vehicle BLKs restore slotless cockpit mods.
megamek/src/megamek/common/loaders/BLKSupportVTOLFile.java	Calls loadSlotlessEquipment to reload slotless mods on support VTOLs.
megamek/src/megamek/common/loaders/BLKSupportTankFile.java	Calls loadSlotlessEquipment to reload slotless mods on support ground vehicles.
megamek/src/megamek/common/loaders/BLKLargeSupportTankFile.java	Calls loadSlotlessEquipment for large support tank BLKs.
megamek/src/megamek/common/loaders/BLKFixedWingSupportFile.java	Calls loadSlotlessEquipment for fixed-wing support aircraft BLKs.
megamek/src/megamek/common/loaders/BLKConvFighterFile.java	Calls loadSlotlessEquipment for conventional fighter BLKs.
megamek/src/megamek/common/loaders/BLKBattleArmorFile.java	Calls loadSlotlessEquipment for battle armor BLKs so slotless cockpit mods are reloaded.
megamek/src/megamek/common/loaders/BLKAeroSpaceFighterFile.java	Calls loadSlotlessEquipment for aerospace fighter BLKs.
megamek/src/megamek/client/ui/entityreadout/ReadoutUtils.java	Adjusts hideMisc to always show DNI, EI, and DIC even when mounted in LOC_NONE.
megamek/src/megamek/common/templates/VehicleTROView.java	Overrides skipMount to hide CASE/armor/structure at LOC_NONE while displaying cockpit mods in vehicle TROs.
megamek/src/megamek/common/templates/SupportVeeTROView.java	Same skipMount override for support vehicles so cockpit mods are visible in TROs.
megamek/src/megamek/common/templates/BattleArmorTROView.java	Refines equipment filtering so BA LOC_NONE DNI/EI cockpit mods are shown while other slotless items remain hidden.
megamek/src/megamek/common/templates/AeroTROView.java	Adds skipMount override so aerospace/conventional fighters show cockpit mods but hide CASE/armor/structure at LOC_NONE.
megamek/unittests/megamek/common/CockpitModificationTest.java	Adds MTF and BLK round-trip tests verifying that DNI, EI, and DIC are preserved on Meks and DNI on Tanks.
megamek/unittests/megamek/common/verifier/TestEntityGameYearValidationTest.java	Adds tests for TestMek game-year getter/setter and for treating DNI/EI as retrofittable in intro-year validation, based on entity year vs explicit game year.

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[HammerGS]

Here are some pre-made test units of the various classes.

Test Units.zip