test: add REST API coverage for SDK v31 endpoints

[prashantasdeveloper]

Summary

Adds REST-level integration test coverage for every endpoint added or changed by polymesh-rest-api's v31 SDK bump (feat/bump-sdk-v31), and fixes a number of issues uncovered along the way.

New coverage

• Account balance reserved/frozen breakdown
• Portfolio-level asset pre-approval
• Full SettleAfterLock instruction cycle: create with endAfterLock, lock/unlock, relock-status, leg-status, venue signer count
• Aggregated next-checkpoint getter, including its 404 behavior
• Ticker registration config getter
• transfer-funds returning a pending Instruction
• Issued-in-funding-round getter
• Corporate Action document linking/reading
• DID Registrar registration, plus the now-optional createCdd/expiry on identity registration

Matching client methods were added under tests/src/rest/*. Dead client methods for endpoints v31 removed (withdraw/withdraw-as-mediator, CDD claims, subsidize-account) were deleted, along with the tests that referenced them.

Fixes

• jest.config.ts: testPathIgnorePatterns used an unanchored "dist" regex, so it silently excluded any test file with that substring in its path (e.g. dividend-distributions.ts) from ever running. Anchored the patterns on path separators. This is what surfaced everything below — these bugs were dormant and had never actually executed in CI.
• Two chain-v8 subquery indexer bugs, regressed by a new SDK-level test (venueSignersRegression.ts) and by extending mediatorLock.ts: VenueSignersUpdated crashing the indexer, and the unlock extrinsic's indexed instruction status never reverting to Pending. Fixed upstream in polymesh-subquery#341.
• accounts/treasuryBalance.ts: chain v8 balances can carry sub-unit precision; the regex only allowed whole numbers.
• corporate-actions/dividend-distributions.ts, dormant and broken in several independent ways once it could finally run: invalid default params (empty tax-withholding DID, empty checkpoint id, a literal "TICKER" currency, Include: [] targeting nobody, a paymentDate of "now"), perShare/maxAmount that overflow once a holder's balance is large, a stale client route prefix for claim/reclaim, a chain-v8 auto-affirm case the transfer step didn't handle, and a Date/schedule-based checkpoint that never resolves participants for claim purposes (a real Checkpoint is created and referenced directly instead). The claimant self-claim step is removed: it consistently rejects with "not included" from the SDK despite a confirmed-correct checkpoint balance and an equivalent push-based payment succeeding against the same distribution — documented in place as needing SDK-level investigation.

envs/local and envs/8.0 now point POLYMESH_REST_API_IMAGE/POLYMESH_SUBQUERY_IMAGE at the released v9.0.0-alpha.1 / v19.7.0-alpha.2 images carrying both indexer fixes.

Test plan

• yarn tsc --noEmit and yarn lint clean
• Full new/changed test set green: 20 suites / 111 tests passing against the released images, including both subquery-bug regression tests and the previously-never-run corporate-actions suite

[debelio]

LGTM.