feat: Add rustfmt configuration and enhance workspace linting rules

- Add .rustfmt.toml with comprehensive formatting rules for consistent code style
- Set max_width to 100 and tab_spaces to 4 with edition "2026"
- Enable import reordering and grouping with StdExternalCrate strategy
- Configure comment wrapping at 80 characters and enable comment normalization
- Enable field init shorthand, try shorthand, and format code in doc comments
- Set trailing comma to "Vertical" and match_block_trailing_comma to true

Cargo.toml

@@ -8,7 +8,7 @@ resolver = "2"
 [workspace.package]
 version = "1.0.0"
 authors = ["TaaS Team <[email protected]>"]
-edition = "2021"
+edition = "2026"
 rust-version = "1.94"
 license = "MIT"
 
@@ -22,9 +22,14 @@ unsafe_code = "forbid"
 [workspace.lints.clippy]
 all = "warn"
 pedantic = "warn"
+nursery = "warn"
 unwrap_used = "deny"
 expect_used = "deny"
 panic = "deny"
+unwrap_in_result = "deny"
+expect_used = "deny"
+unimplemented = "deny"
+todo = "warn"
 
 [workspace.dependencies]
 # Async runtime