refactor: use sdk-native types, improve error handling & modularize output

[suhailkakar]

Note

Medium Risk
Broad refactor touching CLI parsing types and config/key resolution paths; behavior should be equivalent but could introduce breaking CLI arg parsing or new error surfaces if the SDK type parsing differs from the old string validators.

Overview
Switches many CLI arguments from raw String parsing to SDK-native types (Address, B256, U256), removing local parse_address/parse_condition_id helpers and simplifying request building across commands.

Improves runtime configurability and error handling: POLYMARKET_RPC_URL now overrides the default Polygon RPC, and config::load_config/resolve_key/resolve_signature_type return structured Result errors instead of silently failing; related callers were updated accordingly.

Refactors UX/output plumbing by centralizing error printing (output::print_error), lazily initializing API clients in main, and splitting the large CLOB output module into smaller output/clob/* modules; also normalizes wallet/setup key serialization and reuses shared USDC constants.

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