Add rent-reclaim plugin suite: scan (T0) + build (T1) for reclaiming rent from empty token accounts

[uditjainstjis]

What

Two new plugins that recover the ~0.002 SOL rent locked in empty SPL / Token-2022 token accounts:

• rent-reclaim-scan (T0, read-only): scans a wallet's token accounts and reports reclaimable rent (count, per-account breakdown, total SOL).
• rent-reclaim-build (T1, tx-builder): builds an unsigned transaction closing the selected empty accounts, rent returned strictly to the account owner.

Custody & injection safety

The rent destination is not a parameter anywhere in the schema, core, or encoder — it is hard-wired to the account owner, so prompt injection provably cannot redirect funds. A smuggled destination field fails closed via deny_unknown_fields; non-empty, foreign, or frozen accounts are refused all-or-nothing. READMEs include the threat model and a prompt-injection test transcript.

Testing

• 23 unit tests across both plugins (RPC mocked), including fail-closed injection tests and an independent wire-format decoder asserting destination == owner at the byte level
• cargo build --locked --target wasm32-wasip2 --release green for both (~360/385 KB)
• fmt + clippy clean; tools/tests and build-registry.py --check-metadata pass
• Live proof: scan core run against a real mainnet wallet (3049 token accounts); the built unsigned tx passes mainnet simulateTransaction with err: null (real outputs embedded in the READMEs)