Add rustfmt.toml for consistent code formatting

[Priyanshu-rgbb]

Description

The repository requires contributors to run cargo fmt (per CONTRIBUTING.md) but doesn't provide a rustfmt.toml configuration file to enforce project-specific formatting rules

Why this matters

• Without explicit configuration, different contributors might have different rustfmt versions/defaults
• Enforces consistent import organization, line length, and style
• Reduces "formatting noise" in PRs where different rustfmt settings produce different output
• Documents the project's formatting preferences

Files Affected

Create rustcloud/rustfmt.toml

Acceptance Criteria:

• Create rustcloud/rustfmt.toml in the crate directory
• Set edition to "2021" (matches Cargo.toml)
• Configure sensible defaults for line length, imports, etc.
• Run cargo fmt after adding the config to verify no unexpected mass changes
• Document any non-standard choices with inline comments

Proposed Implementation

Rust formatting configuration for RustCloud

edition = "2021"

Code layout

max_width = 100
hard_tabs = false
tab_spaces = 4

Imports

imports_granularity = "Crate"
group_imports = "StdExternalCrate"

Comments

wrap_comments = true
comment_width = 100

Consistency

newline_style = "Unix"

Additional Context

After merging, contributors should run cargo fmt to update their local code. This may produce a one-time large formatting diff—recommend running in a separate "format all" commit if needed.

See rustfmt documentation: https://rust-lang.github.io/rustfmt/