Reverse power flows, unified battery charging port

[ducky64]

Resolves #330.

Adds a reverse voltage direction for VoltageSource/Sink. Only at most one reverse voltage source per connection (and combined with the unique forward VoltageSource requirement, means at most one bidirectional power path). Adds unit tests.

Refactors the LiPo connector, Mcp73831 battery charger IC, and reverse-capable PMOS reverse voltage protector to use this new infrastructure and eliminates the dedicated charging pseudo-port.

This refactors the voltage DummyDevices to the electronics_model to support unit tests. The other ones should eventually be migrated

To check for reverse source uniqueness, this adds some code infrastructure:

• Adds an array-element equals for RangeExpr only
• Adds bool array NOT operation
• Adds compiler unit tests
• Regenerates protos, bumps proto version.

[Copilot]

Pull request overview

Adds opt-in bidirectional (reverse) power-flow modeling to the voltage-port/link infrastructure, then refactors battery/charger-related parts and examples to use it while extending the expression/proto toolchain to support the required array operations.

Changes:

• Extend VoltageSource / VoltageSink / VoltageLink with reverse_* voltage/current parameters and ERC rules (eg, unique reverse voltage source per link).
• Refactor LiPo connector, MCP73831 charger, and PMOS reverse-protection blocks (and examples) to use the unified power port instead of a dedicated charging pseudo-port (with deprecation shims).
• Add proto + compiler support for array element equality (Range only) and boolean-array NOT, bumping the proto version and updating/adding tests.

Reviewed changes

Copilot reviewed 26 out of 27 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
proto/edgir/expr.proto	Adds BinarySetExpr.EQ opcode for pointwise equality.
examples/test_protected_charger.py	Updates charger chaining to use unified bidirectional power port.
examples/test_pcbbot.py	Updates charger chaining to use unified bidirectional power port.
edg/parts/PowerConditioning.py	Refactors PMOS charger reverse-protection block to new reverse-flow params; adds deprecated alias accessors.
edg/parts/Connectors.py	Refactors LipoConnector to remove dedicated chg port and use reverse sink capability on pwr.
edg/parts/BatteryCharger_Mcp73831.py	Models charger battery pin as a reverse-capable VoltageSink (reverse source).
edg/hdl_server/main.py	Bumps EDG proto version.
edg/electronics_model/test_voltage_link.py	Replaces metadata test with compiler-level unit tests including reverse-flow cases.
edg/electronics_model/init.py	Exports dummy devices from electronics_model for unit testing.
edg/electronics_model/VoltagePorts.py	Implements reverse voltage/current propagation + ERC checks; updates bridges to include reverse params.
edg/electronics_model/VoltageDummyDevice.py	Adds voltage dummy devices in electronics_model (with reverse params).
edg/electronics_model/PassivePort.py	Extends passive voltage adapters to include reverse params.
edg/electronics_model/GroundDummyDevice.py	Adds ground dummy device in electronics_model.
edg/electronics_model/DummyDevice.py	Adds base dummy-device type under electronics_model.
edg/edgir/expr_pb2.pyi	Regenerated typing stubs for new proto opcode.
edg/edgir/expr_pb2.py	Regenerated python proto bindings for new opcode.
edg/core/Binding.py	Adds bindings for boolean-array NOT and array EQ (BinarySetExpr.EQ).
edg/core/ArrayExpr.py	Adds ArrayBoolExpr.__invert__ and ArrayRangeExpr.elts_equals().
edg/abstract_parts/init.py	Removes export of DummyDevice from abstract parts.
edg/abstract_parts/DummyDevices.py	Removes local voltage/ground dummy implementations (now provided via electronics_model).
edg/abstract_parts/Categories.py	Removes DummyDevice definition from abstract parts categories.
compiler/src/test/scala/edg/compiler/ExprEvaluateTest.scala	Adds evaluation tests for unary-set negate on bool arrays and BinarySet EQ.
compiler/src/main/scala/edg/compiler/ExprToString.scala	Adds stringification for BinarySetExpr.EQ.
compiler/src/main/scala/edg/compiler/ExprEvaluate.scala	Implements evaluation for BinarySet EQ and boolean-array negate.
compiler/src/main/scala/edg/compiler/Compiler.scala	Bumps expected proto version.
compiler/src/main/scala/edg/ExprBuilder.scala	Adds Literal.RangeEmpty() helper for tests/builders.

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[Copilot]

This import introduces a circular dependency: edg.electronics_model.init imports DummyDevice, but DummyDevice imports from ..electronics_model (the package init). Importing electronics_model will recurse and can fail with partially initialized symbols. Import abstract_block / InternalBlock directly from edg.core (or the defining module) instead of from the electronics_model package aggregator.

Suggested change

	from ..electronics_model import abstract_block, InternalBlock
	from ..core import abstract_block, InternalBlock

[Copilot]

The comment says the battery current range is clamped to a 0 lower bound, but the updated expression no longer hulls with (0, 0). Either reintroduce the explicit 0 lower-bound clamp or update the comment to match the new behavior (and ensure negative ranges can’t occur if that’s a requirement).