Control which taproot script path to spend (#33084) #35702

• PSBTFillOptions (src/common/types.h): Introduced keypath_only (bool) and taproot_script_path (optional hex string) fields.
• PSBT Signing (src/psbt.cpp): Updated SignPSBTInput to intercept the script data inside SignatureData::tr_spenddata.scripts before passing them to ProduceSignature. This prevents the wallet from appending unused taproot scripts into the PSBT.
• RPC Support (src/wallet/rpc/spend.cpp & src/rpc/rawtransaction.cpp): Added keypath_only and taproot_script_path as optional arguments to both walletprocesspsbt and descriptorprocesspsbt.
• Client Mapping (src/rpc/client.cpp): Registered keypath_only in vRPCConvertParams so that bitcoin-cli properly casts it as a boolean.

Fixes #33084.

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For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/35702.

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Closing this for the same reason as stated in #35703 . @kallal79 you are required to explain your changes and why they are implemented in the way they are in your own words to contribute here.