IoT fan + led driver combo, new parts, I2C controller bridge

[ducky64]

Refactors the IoT fan driver example to be a combination fan driver / 12v-capable neopixel driver. Changes it to a two-level board, adds sensors and the choice of USB PD input. Layout to be completed as a separate PR, which may also require changing the pinning and circuit split between levels.

Removes IoT knob example, which is now redundant.

Component library changes:

• Add optional resistance to I2cPullup
• Add I2cController bridge, allow I2cController to have addresses (mostly to encode inner devices), with tests
• Add OE pin to 74xx1g125
• Add VL53L5CX

Core / compiler changes:

• Add array concatenation operation to compiler, using addition op
• Add tolerance-shrinking subtract to compiler, though not plumbed through to frontend yet
• Regenerate proto

[Copilot]

Pull request overview

This PR expands the PolymorphicBlocks hardware DSL/compiler and example set: it refactors the IoT fan example into a fan + (12V-capable) LED driver combo with a two-level “control subboard” concept, removes the redundant IoT knob example, and extends the core HDL/compiler and parts library (notably I2C nesting/bridging, array concatenation expressions, and a new VL53L5CX distance array sensor).

Changes:

• Refactor IotFan into a multi-board design with USB-C PD option, added sensing, and updated netlist/layout artifacts; remove IotKnob example + generated layout files.
• Extend I2C modeling: optional pullup resistance, controller “nested address propagation” via a controller bridge, and additional compile-time checks + tests.
• Extend compiler/proto: add SHRINK_SUB range op and implement array concatenation via ADD, with updated evaluation/stringification and regenerated protobuf bindings.

Reviewed changes

Copilot reviewed 26 out of 30 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
proto/edgir/expr.proto	Adds SHRINK_SUB opcode to the expression proto.
edg/hdl_server/main.py	Bumps EDG proto version to match regenerated protobufs.
edg/electronics_interfaces/test_i2c_link.py	Adds tests for nested I2C controller address propagation and redundant pullup detection.
edg/electronics_interfaces/I2cPort.py	Adds controller bridge + controller addresses and tightens I2C pullup rules.
edg/edgir/expr_pb2.pyi	Regenerated typing stubs to include the new proto opcode.
edg/edgir/expr_pb2.py	Regenerated protobuf Python bindings to include the new proto opcode.
edg/core/ArrayExpr.py	Adds concat() helper for array concatenation backed by ADD.
edg/circuits/I2cPullup.py	Makes I2C pullup resistance configurable.
edg/circuits/I2cBitBang.py	Updates I2C controller port construction to the new I2cController initializer pattern.
compiler/src/test/scala/edg/compiler/ExprEvaluateTest.scala	Adds tests for SHRINK_SUB and for array concatenation via ADD.
compiler/src/main/scala/edg/compiler/ExprToString.scala	Adds stringification for SHRINK_SUB.
compiler/src/main/scala/edg/compiler/ExprEvaluate.scala	Implements array concatenation for ADD and SHRINK_SUB evaluation.
compiler/src/main/scala/edg/compiler/Compiler.scala	Bumps expected proto version to match the updated schema.
examples/test_iot_knob.py	Removes the IoT knob example test.
examples/test_iot_fan.py	Refactors IoT fan into a two-level design and adds USB-C PD + sensors + NeoPixel/fan control changes.
examples/IotKnob/resources/svgpcb-ledring.js	Removes knob SVGPCB resource as part of knob example removal.
examples/IotKnob/IotKnob.svgpcb.js	Removes generated knob SVGPCB layout artifact.
examples/IotKnob/IotKnob.kicad_pro	Removes knob KiCad project file.
examples/IotKnob/fp-lib-table	Removes knob footprint library table file.
examples/IotFan/IotFan.svgpcb.js	Updates generated SVGPCB layout artifact for the refactored IoT fan design.
examples/IotFan/IotFan_control.net.ref	Adds/updates reference netlist for the new “control” sub-board netlist output.
examples/edg.pretty/ST_VL53L5x.kicad_mod	Adds a KiCad footprint for the VL53L5x family package.
edg/parts/sensor/DistanceArray_Vl53l5cx.py	Adds a new VL53L5CX distance array sensor part (with decoupling + pulls).
edg/parts/sensor/init.py	Re-exports the new Vl53l5cx part.
edg/parts/logic/Logic_74Ahct.py	Adds OE support to 74AHCT1G125 and exposes optional enable on the wrapper.

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