Port solc standard JSON compile corpus

Bun compatibility slice

Port js/third_party/solc/solc.test.ts at exhaustive corpus position 4061.

Required behavior

• support the default solc import and compile() standard-JSON entry point;
• parse Solidity source units and return deterministic contracts/sources output for a simple program;
• report source-level compiler problems in the returned standard JSON rather than throwing;
• throw a structured, causal, operation-tagged error for malformed API input without exposing source payloads;
• add focused and permanent regression coverage.

Tracked from #66.

Implemented and pushed in 941fa6134.

Coverage now includes:

• default solc import and standard-JSON compile() entry point;
• deterministic source IDs, contract discovery, function ABI entries, metadata, and bytecode/deployed-bytecode objects;
• in-band standard-JSON diagnostics for unsupported language, malformed sources, and unbalanced Solidity braces;
• SolcCompileError for malformed API input with code, operation, phase, input length, sanitized cause, and causal stack;
• source-payload redaction from exception messages and stacks;
• permanent behavioral proof that compilation returns a populated contract rather than a no-op value.

Verification:

• focused position 4061: 1 file, 1 passed, 0 failed/todo/unsupported/allowed-empty;
• positions 4060–4061: 2 files, 1 passed, 1 intentional todo, 0 failed/unsupported/allowed-empty;
• permanent gRPC error-stack, SQL adapter-contract, third-party corpus, and 38-case behavior/error diagnostic suites all pass.