feat: support TOML 1.1 multiline inline tables

Bump toml_edit to 0.25 (toml and toml-span already support TOML 1.1 on
main). Add insert_into_inline_table_with_format to preserve multiline
formatting, indentation style, and trailing comma conventions when
inserting new entries.

Includes comprehensive tests: direct unit tests for the formatting
function (trailing commas, sequential insertions, empty tables, tab
indentation, single-line fallback, existing key updates, non-dependency
tables), integration tests through TomlDocument, and consolidated
parse-only tests for upstream TOML 1.1 support. All tests use inline
insta snapshots.

https://claude.ai/code/session_01FT59TTz4yRy3DPwbREE82u

Author: claude

Cargo.lock

@@ -175,7 +175,7 @@ tokio-test = "0.4.5"
 tokio-util = "0.7.13"
 toml = "1.0.0"
 toml-span = "0.7.0"
-toml_edit = "0.23.0"
+toml_edit = "0.25.0"
 tracing = "0.1.41"
 xz2 = "0.1.7"
 # Forcing the version due to this PR https://github.com/tokio-rs/tracing/pull/3368