[Store] Structure AdminHttpBootstrapConfig settings

[bitborne]

Description

Extract the embedded HTTP metadata server's enablement, port, and host into AdminHttpBootstrapConfig. The loader owns defaults and the existing precedence of flat YAML/JSON keys followed by explicitly supplied CLI flags. No new public keys or grouped configuration schema are introduced; the metadata-cleanup setting remains separate.

Validate the effective port before converting it to the server's uint16_t port type. Values outside 0..65535 now produce a startup configuration error instead of silently selecting a different port; 0 remains accepted. This follows the validation and scope lessons from #4275 and advances the internal ownership work in #3809 / #2694. Unlike the older #2256, this PR does not move HTTP server ownership into the HA supervisor or change metadata cleanup behavior.

Module

• Transfer Engine (mooncake-transfer-engine)
• Mooncake Store (mooncake-store)
• Mooncake Conductor (mooncake-conductor)
• Reshard (mooncake-reshard)
• Mooncake EP (mooncake-ep)
• Mooncake PG (mooncake-pg)
• Integration (mooncake-integration)
• P2P Store (mooncake-p2p-store)
• Python Wheel (mooncake-wheel)
• Common (mooncake-common)
• Mooncake RL (mooncake-rl)
• CI/CD
• Docs
• Other

Type of Change

• Bug fix
• New feature
• Refactor
• Breaking change
• Documentation update
• Performance improvement
• Other

How Has This Been Tested?

Test commands:

cmake --build build --target http_metadata_server_test mooncake_master -j222
ctest --test-dir build -R '^http_metadata_server_test$' --output-on-failure
build/mooncake-store/src/mooncake_master --http_metadata_server_port=-1
build/mooncake-store/src/mooncake_master --http_metadata_server_port=65536
./scripts/code_format.sh --staged --check

Test results:

• Unit tests pass: 8 configuration tests and the existing 3 HTTP metadata server tests.
• Integration tests pass (if applicable): http_metadata_server_test passed 11/11 tests.
• Manual testing done: both invalid CLI ports exited with a clear range error.
• Pre-commit hooks passed on all seven changed files.

Checklist

• I have performed a self-review of my own code
• I have formatted my code using ./scripts/code_format.sh
• I have run pre-commit on the files changed in this PR and all hooks pass
• I have updated the documentation (not applicable; this internal refactor does not change the public configuration schema)
• I have added tests to prove my changes are effective
• For changes >500 LOC: I have filed an RFC issue (not applicable; this focused PR contributes to [Track]: Mooncake Store Configuration and Environment Convergence #3809 and [RFC]: [Store] Master Configuration Refactoring #2694)

AI Assistance Disclosure

• No AI tools were used
• AI tools were used (specify below)

Codex assisted with the scoped implementation, tests, and review. The human submitter is responsible for reviewing every changed line and defending the change end-to-end.