Refactor/runtime config modules

[nol4lej]

What's in here

Three independent changes, one commit each, each compiling on its own.

1. Runtime configs split into modules (83d64c04)

template/runtime/src/lib.rs drops from 1444 to 1053 lines. The impl Config blocks move to template/runtime/src/configs/, grouped by concern:

Module	Lines	Contents
system.rs	108	frame_system, timestamp, balances, transaction payment, sudo
consensus.rs	124	aura, grandpa, session, validator-set, authorship
evm.rs	112	pallet_evm, ethereum, base fee, chain id, precompiles
privacy.rs	80	shielded-pool, zk-verifier, relayer

lib.rs keeps construct_runtime!, the version, the Executive types, and the inline pallet_manual_seal config (the macro requires it in the crate root).

Two details that aren't cosmetic: modules use crate::* rather than super::*, because Runtime is generated by construct_runtime! after the module declarations; and the re-export is explicit per module, since a plain glob over configs does not forward submodule items — that omission broke SS58Prefix in the node and BlockWeights under try-runtime.

No functional change: same pallets, same parameters, same weights.

2. Minimum shield amount removed (d3a89361)

Drops the MinShieldAmount constant (1 ORB in the runtime) and the AmountTooSmall error. shield accepts any non-zero amount.

The floor kept small deposits out of the pool without buying much: it does not bound storage, since one leaf costs the same at 1 planck as at 1 ORB, and the transaction fee already prices the write. What it did do is force a user holding a fractional balance to leave it unshielded.

Zero is still rejected, through the existing InvalidAmount — a zero-value note takes a leaf and a memo slot while carrying nothing. The EVM precompile keeps its own zero-value guard at the ABI boundary.

3. Validator registration bond removed (8ff67f4e)

Drops the ValidatorBond and Currency Config items, the ValidatorBondOf storage map, both bond events, InsufficientBond, and the release_bond helper. register_validator is now free.

What gates registration is unchanged and was always the part doing the work: session keys plus a registered EVM relayer, a pending queue bounded by MaxPendingValidators, and no account entering the active set without an explicit approve_validator from sudo. A bond deters spam that governance approval already blocks, and on a testnet where operators are onboarded by hand it only added a funding step.

Consensus is expected to change before mainnet; a staking-based scheme will bring its own economic gate.

Compatibility

No migration. ValidatorBondOf was queried on testnet before removal: 0 entries, empty pending queue, 3 validators all added via sudo. Nothing is left reserved. A chain with live bonds would need one.

Error indices shift. AmountTooSmall sat at index 6 in the shielded-pool Error enum, so every variant after it moves down one. Verified that app matches on the error name, not the index — unaffected. Anything decoding by index needs fresh metadata.

Precompile ABI unchanged. Same selectors, parameters and layout; only the set of calls the chain accepts widened.

Versions

pallet-validator-set 0.1.0 → 0.2.0 and pallet-evm-precompile-shielded-pool 0.3.0 → 0.4.0. Both breaking, but 0.x carries breakage in the minor.

spec_version stays at 7 — it was never deployed, so these collapse into that bump. transaction_version does not move; no call signature changed.

Verification

83d64c04 compiles alone	✅ 9m 06s
d3a89361 compiles alone	✅ 5m 39s
Unit tests	✅ 423 (308 shielded-pool, 65 precompile, 50 validator-set)
Runtime + try-runtime + runtime-benchmarks	✅
Dev-node E2E	✅ 11/11

Each commit was verified in isolation by extracting its tree and building it separately. Not ceremony: an earlier version of this branch had all three commits broken, because the refactor commit carried a Config assignment belonging to an uncommitted change while the pallet did not declare it (error[E0437]). Caught and fixed with a rebase.

The new E2E (ts-tests/no-bond-no-min-shield.test.cjs) covers both removals: constants, storage, events and errors absent from metadata; a 1-planck shield reaching the pool balance; zero still refused; and an account holding 1 ORB — a thousandth of the old bond — reaching the prerequisite gate instead of failing on funds, reserving nothing.

Out of scope

app is left with dead code that does not break it (degrades to null, a case already handled) and should be cleaned separately: services/shielded-pool/limits.ts, its test, the validation in ShieldPanel.tsx:44, and the AmountTooSmall entry in chainErrors.ts:27.