Mj/file store err flip

[michaeldjeffrey]

Move Domain-Specific Errors from file-store to Implementers

Summary

This PR restructures error handling in the file-store library by moving domain-specific errors to the types implementing TryFrom conversions. This separation of concerns keeps file-store focused on library-level errors while allowing each domain to handle its own conversion errors appropriately.

Changes

file_store::Error Cleanup

The file_store::Error enum has been significantly reduced to contain only errors that can be returned from file-store library code:

• IO, encoding, channel, AWS, crypto, and database errors remain
• All domain-specific errors (IoT, mobile, subscriber) have been removed
• Domain errors now live in the Error type of their respective TryFrom implementations

Custom Domain Error Types

Created domain-specific error types in file-store-oracles.
Each file has it's own Error type that maps things that can fail during those types conversions.

Some common errors include

#[error("invalid timestamp: {0}")]
Timestamp(#[from] TimestampDecodeError),

#[error("missing field: {0}")]
MissingField(&'static str),

MsgDecode Trait Enhancement

The MsgDecode trait now includes a custom error variant:

pub enum MsgDecodeError<E> {
    Prost(prost::DecodeError),
    Conversion(E),
}

This allows implementers to return domain-specific errors from the TryFrom conversion without coupling to file-store's error types.

MsgTimestamp Trait Relocation

The MsgTimestamp trait has been removed from file-store due to Rust's orphan rules. When implementing this trait for both proto and domain types, you need to own the trait definition. The trait definition and usage examples are documented in the timestamp.rs file with guidance for implementers.

Timestamp Handling Improvements

• TimestampDecode trait and TimestampDecodeError remain in file-store for shared timestamp logic
• TimestampEncode trait added for encoding DateTime to various timestamp formats
• Domain implementations can now use timestamp decoding without coupling their error types to file-store

Enum Conversion Utility

Added prost_enum helper function in file-store-oracles:

pub fn prost_enum<Enum, Op, Err>(value: i32, map_err: Op) -> Result<Enum, Err>
where
    Enum: TryFrom<i32, Error = prost::UnknownEnumValue>,
    Op: FnOnce(prost::UnknownEnumValue) -> Err,

This provides a consistent way to convert prost i32 values to enums while properly propagating errors. The mapper automatically determines the enum type from context and allows custom error handling.

FileInfoPollerParser Changes

Updated to allow user errors to pass through from TryFrom implementations, enabling better error context propagation from domain-specific conversions.

IoT Beacon Conversion

The conversion from IotBeaconReport to a regular beacon no longer returns a Result as it's a pure transformation.

Code Organization

• Struct fields in domain types have been reordered where necessary to satisfy Rust's lifetime rules during conversions
• File-store dependency in file-store-oracles reduced with removal of domain error types