feat: Ripple family support (ripple, ripple-testnet)

[artemrootman]

What

Adds the Ripple / XRP Ledger blockchain family (BlockchainType = "ripple"), covering mainnet and testnet. Not to be confused with the xrpl chain (the XRPL EVM sidechain, already served by the EVM family).

Design doc: docs/superpowers/specs/2026-07-17-ripple-support-design.md.

Stacked on #283 (near family); will retarget to main once it merges.

How

• ripple_specific: poll-based validated-ledger head (deliberately not ledger_closed, which can return a not-yet-validated ledger; validated is XRPL finality and carries parent_hash). Poll-only — XRPL subscriptions are WS-command-framed, out of v1 scope.
• Response normalization: XRPL application errors arrive as HTTP 200 {result:{status:"error"}} and clients (xrpl.js) expect that wire shape. A per-spec wildcard translator converts only node-health codes (noNetwork, noCurrent, noClosed, tooBusy, amendmentBlocked, notReady, failedToForward) into retryable errors so failover engages; everything else passes through byte-exact.
• ripple_validations: network-id chain validation (the field is absent on mainnet = 0) and server_state health with a corrected state ladder (full/validating/proposing/tracking available, connected/syncing syncing, amendment_blocked hard-down).
• ripple_bounds: real complete_ledgers parsing (single/disjoint/"empty"; start of the last range). Introduces the DecreasingBoundDetector capability: an archival rippled backfills history backwards, so its lower bound legally decreases — the shared processor's monotonic filter now honors that opt-in (only ripple opts in; other families unchanged).
• ripple_labels: clio_version → clio, else build_version → rippled.
• Method spec: 38-method surface (dshackle parity minus subscribe/unsubscribe — over public HTTP those are an admin-only callback mode), submit/submit_multisigned broadcast (idempotent by tx hash + account sequence), all cacheable: false in v1.

Testing

• Unit tests across all new packages incl. the decreasing-bound processor path and the network-id-absent case.
• Live corpus against production rippled 3.2.0 mainnet + testnet nodes: 46/46 identical, byte-exact result objects for all deterministic cases including error passthroughs and the ledger_data pagination marker. Details in the design doc.