fix: rename STRK20 sub-accounts to shadow accounts (spec PR 406)

[PhilippeR26]

Summary

Applies starknet-specs PR #406
(merged 2026-08-11): the STRK20 sub-account concept is renamed to shadow account
across the wallet API. Terminology only — no semantic or structural change.

Target version: 0.10.4-beta.2.

Breaking (wire-visible)

Before	After
wallet_strk20SubaccountCommitment	wallet_strk20ShadowAccountCommitment
STRK20_SUBACCOUNT_INVOKE_ACTION	STRK20_SHADOW_ACCOUNT_INVOKE_ACTION
"subaccount_invoke" (action discriminator)	"shadow_account_invoke"

STRK20_SUBACCOUNT_INVOKE_ACTION is re-exported both flat and under WALLET_API, so
consumers importing it need to update. No deprecated alias is provided: STRK20 only
landed in 0.10.3, the 0.10.4 line is still in beta, and an alias would not have
covered the two other changes — the RPC method key and the "subaccount_invoke"
discriminator are wire values, not types.

Changes

src/wallet-api/components.ts

• STRK20_SUBACCOUNT_INVOKE_ACTION → STRK20_SHADOW_ACCOUNT_INVOKE_ACTION, with its
  type discriminator 'subaccount_invoke' → 'shadow_account_invoke'.
• STRK20_ACTION union member updated accordingly.
• Doc comments of STRK20_DAPP_NAME, STRK20_COLLECT_POLICY and the invoke action
  realigned word-for-word on the new spec wording (including "shadow account anonymizer").

src/wallet-api/methods.ts

• wallet_strk20SubaccountCommitment → wallet_strk20ShadowAccountCommitment. Params,
  result and error set are unchanged.
• Method doc realigned on the new spec wording.

Validation

• npm run ts:check — passes.
• ./node_modules/.bin/biome lint --write . — no fixes applied.
• grep -riE "sub[_ -]?account" src/ — no occurrence left.

[github-actions]

🎉 This PR is included in version 0.10.4-beta.2 🎉

The release is available on:

• npm package (@beta dist-tag)
• GitHub release

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