….0.0-alpha.1

The c2m-bridge pallet (PR midnightntwrk/midnight-node#1386 et al.) lands
in node 2.0.0-alpha.1 metadata, so the scaffold that was previously
blocked on missing metadata can be activated. The pallet ships inert;
events only fire after governance enables it (set MainChainScripts +
data checkpoint), so this just establishes the decoding path.

Changes:

- `runtimes.rs::BlockDetails`: uncomment `bridge_pallet_events` field.
- `runtimes/v2_0_0.rs`: declare local `bridge_pallet_events` accumulator,
  add full `Event::C2MBridge(_)` match arm decoding all 5 variants
  (UserTransfer, ReserveTransfer, InvalidTransfer, UnapprovedTransfer,
  SubminimalFlushTransfer), and return them via BlockDetails.
  - `recipient.0.0` resolves as `Vec<u8>` directly (drop the earlier
    `.into_inner()` — BoundedVec wrapper not present in the regenerated
    metadata).
- `runtimes/v1_0_0.rs`, `runtimes/v0_22_0.rs`: return
  `bridge_pallet_events: vec![]`. The pallet does not exist in node 1.0
  or 0.22 metadata; the v1_0_0 scaffold (commented out, with a TODO) is
  removed and replaced with a one-line pointer to v2_0_0.
- `subxt_node.rs`: destructure `bridge_pallet_events` from BlockDetails
  and wire it through to the `Block` construction, replacing the
  `Default::default()` placeholder. Add a `DecodeBridgeRecipient`
  variant on `SubxtNodeError` so `BridgeRecipient::new(...)` failures
  propagate via `?` instead of being shoe-horned into the
  `DecodeEvent(Box<EventsError>)` variant.
- Migration: rename `indexer-common/migrations/sqlite/004_bridge_events.sql`
  to `005_bridge_events.sql` to resolve the collision with main's
  `004_block_tree_end_indexes.sql` (PR #1197).
  Postgres bridge migration stays at `004_bridge_events.sql` (no
  collision there).

Build clean on `cargo check --workspace --features cloud` and
`--features standalone`, clippy clean with `-D warnings` on both
features (env vars sourced from `.envrc`), schema regen no-op (the
bridge GraphQL surface was already in place from earlier bridge
commits on this branch).

Remaining unfinished work (not in this commit, separate plumbing
chain):

- `ClaimKind::CardanoBridge` -> `BridgeClaim` storage path
  (`indexer-common/src/domain/ledger/ledger_state.rs` ClaimRewards arms
  for v8 and v9, `ApplyRegularTransactionOutcome.bridge_claim` plumbing,
  `chain-indexer/src/domain/transaction.rs::RegularTransaction.bridge_claim`,
  `chain-indexer/src/infra/storage.rs::save_regular_transaction` calling
  the already-present `save_bridge_claim`). All TODOs marked
  `TODO(bridge):` in the affected files.