Add 20 researched header modules with PCB and schematic snapshots

[seveibar]

Summary

• add 20 breadboard-friendly header modules with idiomatic TSX components and per-module PCB/schematic snapshots
• use the dedicated headermodule footprint name for pluggable board modules while preserving pinrow for ordinary headers
• normalize common power pin identifiers so renders remain valid (3.3V -> V3_3, +3V3 -> V3_3, +5V -> V5)
• assert that each snapshot test creates no source component errors, preventing black/empty footprint snapshots from being accepted
• style header-module footprints with a rectangular silkscreen border, concise per-pin PCB labels, and a short module title such as XIAO RP2040

Why

tscircuit pin identifiers support letters, numbers, and underscores. The previous power labels containing + or . were filtered out by core, which could leave a component creation error behind and produce an empty/black render. The module metadata still uses the real voltage values (3.3V and 5V); only the pin identifiers are normalized.

The corresponding core warning/error guidance is in tscircuit/core#2976.

The headermodule, independent-row/sparse-grid, and silkscreen styling syntax is implemented in tscircuit/footprinter#761, and core preserves literal custom silkscreen labels in tscircuit/core#2980.

Verification

• bun test tests/footprints.test.ts tests/sample-board.test.ts (17 pass)
• bun run typecheck
• bun run build
• npx tsci check schematic-placement index.circuit.tsx
• npx tsci check schematic-placement sample-boards/xiao-rp2040-a4988-stepper-controller.circuit.tsx