docs: add Base Mini PoA (TR/EN) example

[0xDoubleShot]

Adds a minimal PoA-style educational example for Base builders:

• Local devnet bootstrap (Docker)
• Simple contract deploy + client call
• README in EN + short TR notes
• one-shot quickstart.sh + preview image

Motivation: provide a fast onramp for new builders (esp. Turkish community).
Tested locally on Node 18 + Docker Desktop.

Repo reference: https://github.com/0xDoubleShot/base-mini-poa-tr

[cb-heimdall]

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