feat: Export ledger name spaces via server_definitions

[dangell7]

High Level Overview of Change

Adds a LEDGER_NAME_SPACES section to the server_definitions RPC response. It exports the name → value map of the LedgerNameSpace tagged-hash prefixes so clients can compute keylets offline instead of hard-coding the ASCII prefixes or round-tripping to a server.

Context of Change

Clients that want to derive ledger object indexes (keylets) locally need the type-specific prefixes used in the tagged hashing. Today those only exist as a private enum in Indexes.cpp, so every client library carries its own copy and has to chase new amendments by hand. server_definitions already exports fields, ledger entry types, transaction types, etc. for exactly this reason — this just extends it to name spaces.

The enum moves from Indexes.cpp into Indexes.h and is generated from a single X-macro list (detail/ledger_name_spaces.macro). The same list co-generates ledgerNameSpaceMap(), so the enum and the exported map cannot drift — adding a name space in one place updates both. Deprecated name spaces (Contract, Generator, Nickname) stay in the list to reserve their values but are intentionally NOT exported, since keylets should never be computed for retired spaces.

The alternative was exporting a hand-written map next to the enum, but that's two lists to keep in sync and the whole point is to stop copies drifting.

API Impact

• Public API: New feature (new methods and/or new fields)
• Public API: Breaking change (in general, breaking changes should only impact the next api_version)
• libxrpl change (any change that may affect libxrpl or dependents of libxrpl)
• Peer protocol change (must be backward compatible or bump the peer protocol version)

[xrplf-ai-reviewer]

No issues.

Review by Claude Sonnet 4.6 · Prompt: V15

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 82.5%. Comparing base (5ce0b1c) to head (c7bfd6a).

Additional details and impacted files

@@           Coverage Diff           @@
##           develop   #7823   +/-   ##
=======================================
  Coverage     82.5%   82.5%           
=======================================
  Files         1039    1040    +1     
  Lines        80446   80487   +41     
  Branches      9080    9080           
=======================================
+ Hits         66332   66369   +37     
- Misses       14105   14109    +4     
  Partials         9       9           

Files with missing lines	Coverage Δ
include/xrpl/protocol/Indexes.h	100.0% <ø> (ø)
...lude/xrpl/protocol/detail/ledger_name_spaces.macro	100.0% <100.0%> (ø)
src/libxrpl/protocol/Indexes.cpp	96.1% <100.0%> (+0.1%)	⬆️
...pld/rpc/handlers/server_info/ServerDefinitions.cpp	98.0% <100.0%> (+<0.1%)	⬆️

... and 1 file with indirect coverage changes

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[xrplf-ai-reviewer]

No issues found. Code looks good!

Review by Claude Sonnet 4.6 · Prompt: V15