fix: preserve terminals on multi-pin switch imports

[GokulPandi-M]

Motivation

While using C2941005 on a real board, I found that the converter treated the six-terminal slide switch as a two-terminal SPST switch. This removed pins 3–6 from the schematic. Repro: #538.

Change

• Use the native switch primitive only for two-terminal switches.
• Preserve the imported EasyEDA symbol and every terminal for multi-terminal switches.
• Add the component reference through the existing {REF} placeholder, so names such as SW1 and SW2 are generated dynamically.

The converter intentionally does not infer SPDT/DPDT topology from pin count alone. For C2941005, the manufacturer drawing uses pins 2 and 5 as the common terminals, while the built-in DPDT symbol uses a different pin topology. Keeping the imported symbol avoids silently changing electrical meaning.

References: JLCPCB C2941005

Ref:

Before	After

Verification

• C2941005 keeps schematic terminals 1–6 and their PCB pad mappings.
• C136720 keeps its five-terminal imported symbol.
• Updated schematic snapshots verify the visible reference.
• Typecheck and formatting pass.
• Full test suite: 210 passed, 0 failed.

This PR does not change PCB, 3D-model handling, or add native switch simulation semantics for multi-terminal imports.

[techmannih]

dont forgot to add reference?