refactor: use thiserror for ExecutionError and typed Operator::new error

[diegomrsantos]

Issue Addressed

Closes #317

Proposed Changes

Improve error handling in the eth crate by introducing thiserror, preserving error chains, and removing duplicate logging.

• Convert ExecutionError from a manual Display impl to thiserror derive with human-readable #[error(...)] messages
• Change DecodeError variant from DecodeError(String) to DecodeError(#[from] alloy::sol_types::Error), preserving the error source chain instead of formatting to string
• Return typed operator_key::ConversionError from Operator::new instead of discarding it via .map_err(|e| e.to_string())
• Remove ~17 duplicate debug!()/error!() logs from inside .map_err() closures and before return Err() in event_processor.rs, sync.rs, and util.rs — the caller already logs every returned error at warn/trace (event processing) or error (sync), so these produced duplicate log entries

Additional Info

• All existing call sites continue to work unchanged — the String-wrapping variants (Database, InvalidEvent, etc.) keep their current signature
• The Display format changes from Debug output (DecodeError("...")) to human-readable (Decode error: ...), which improves log readability
• Converting more variants (e.g. Database) from String to typed source errors is a natural follow-up but left out to keep this PR focused

[Copilot]

Pull Request Overview

Enhance error handling and logging by introducing typed error enums for share parsing, RSA parsing, and execution events, and replacing generic error messages with contextual variants.

• Added ShareParseError and RsaParseError enums using thiserror for richer error information.
• Extended ExecutionError with specific builders (invalid_operator_event, invalid_validator_event, etc.) and updated call sites accordingly.
• Updated parsing and sync logic to use the new error variants and removed or adjusted debug log statements.

Reviewed Changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
eth/src/util.rs	Introduced ShareParseError, updated parse_shares to return it.
eth/src/sync.rs	Switched to ExecutionError::invalid_event builder for errors.
eth/src/network_actions.rs	Added StringError wrapper, updated error constructors.
eth/src/event_processor.rs	Replaced generic errors with contextual builders; removed logs.
eth/src/error.rs	Expanded ExecutionError with new variants and builder methods.
eth/Cargo.toml	Added thiserror as a dependency.
common/ssv_types/src/util.rs	Introduced RsaParseError, updated parse_rsa to return it.
common/ssv_types/src/operator.rs	Updated Operator::new to surface RsaParseError.
common/ssv_types/src/lib.rs	Re-exported RsaParseError.

Comments suppressed due to low confidence (3)

anchor/eth/src/util.rs:37

• The error annotation for EncryptedKeyLength is passing the literal string "actual" instead of the actual field; change the placeholder to {actual} so the runtime value is shown.

#[error("Encrypted key has wrong length: expected {}, got {}", ENCRYPTED_KEY_LENGTH, "actual")]

anchor/eth/src/event_processor.rs:442

• The error message "Failed to validator cluster" is grammatically incorrect; consider updating it to something like "Failed to delete validator from cluster: {e}".

.map_err(|e| ExecutionError::Database(format!("Failed to validator cluster: {e}"))?);

anchor/eth/src/util.rs:50

• [nitpick] New error variants in parse_shares (e.g., InvalidLength, PublicKeyCreation, EncryptedKeyLength) are not covered by existing tests; consider adding unit tests for each failure branch.

pub fn parse_shares(

[dknopik]

Thanks for looking into this! I added some early thoughts

[Zacholme7]

We still planning to keep this or is it closable?

[diegomrsantos]

We still planning to keep this or is it closable?

I wanna do it at some point

[shane-moore]

maybe create gh issue for this?
Converting more variants (e.g. Database) from String to typed source errors is a natural follow-up but left out to keep this PR focused