Bump verify-range stellar-core to Protocol 27 noble build - #192

* Protocol 27 ingestion (#186)

* Protocol 27 (CAP-0071 + CAP-0083) ingestion support

- Pin go-stellar-sdk to the CAP-71/CAP-83 XDR build.
- Bump MaxSupportedProtocolVersion to 27.
- Implement GetLedgerRaw on fakeLedgerBackend (added to the SDK
  LedgerBackend interface).

* update core test lcm

* add GetLedgerRaw

* update

* Bump go-stellar-sdk to CAP-71-only XDR; drop CAP-83 fixture

go-stellar-sdk@130456cc9b69 is regenerated from stellar-xdr@68fa1ac (post-
stellar/stellar-xdr#303 ungate of CAP_0071) with XDR_FEATURES cleared, so
the bind no longer carries the CAP-0083 STELLAR_VALUE_EMPTY_TX_SET path —
matching the p27 release scope (CAP-0071 only; CAP-0083 deferred).

The SDK bump also transitively picks up stellar/go-xdr#32, which raises
DecodeDefaultMaxDepth 250 → 1500, so the CAP-71 240-deep delegate fixture
(test-lcms/InvokeHostFunctionTests/a7a45d93c64cf3d9.xdr) now ingests
without ErrMaxDecodingDepth.

The HerderTests fixture (network_externalizes_empty-tx-set_on_missing_value)
no longer decodes under CAP-71-only XDR (StellarValueType 2 is gone) and is
removed.

* Bump go-stellar-sdk to latest CAP-71-only build (a8d5b306)

* Bump protocol 26 core version to 27.0.0-3288.7696c069d

* Support core 27 apply-load config in TestGenerateLedgers

Core 27 reworked the apply-load configuration: the sampled load
parameters (APPLY_LOAD_INSTRUCTIONS, APPLY_LOAD_TX_SIZE_BYTES,
APPLY_LOAD_NUM_RW_ENTRIES, etc.) were removed in favor of an
APPLY_LOAD_MODE selector, and the apply-load command now force
overrides NETWORK_PASSPHRASE to "Apply Load" and runs at the core's
current ledger protocol version.

- Add testdata/apply-load-v27.cfg based on core 27's
  docs/apply-load-for-meta.cfg
- Select the default config based on the core binary's major version
- Assert ledger protocol version against the core binary's reported
  protocol version instead of the max supported protocol env var

* Add v27 load-test fixtures; restore deep-delegate LCM fixture

- Add load-test-ledgers-v27.xdr.zstd / load-test-fixtures-v27.xdr.zstd,
  generated via TestGenerateLedgers using the same stellar-core build CI
  pins (27.0.0-3288.7696c069d, buildtests). Fixes
  TestLoadTestLedgerBackendWithoutMerge, which looks up the fixture for
  MaxSupportedProtocolVersion (now 27).
- Core 27's apply-load command force-overrides the network passphrase to
  "Apply Load", so the load tests now select the fixture passphrase by
  protocol version.
- Restore the 240-deep CAP-71 delegate-tree LCM fixture
  (InvokeHostFunctionTests/a7a45d93c64cf3d9.xdr, still referenced by
  index.json): it was dropped while go-xdr's max decoding depth was 250,
  and ingests cleanly again with stellar/go-xdr#32 (depth 1500).

* Bump integration tests to use Protocol 27 (#189)

* Bump go-stellar-sdk to v0.6.0 (#191)

* Bump verify-range stellar-core to Protocol 27 noble build (#192)

---------

Co-authored-by: Siddharth Suresh <[email protected]>
Co-authored-by: urvisavla <[email protected]>