chore: enable snafu rust_1_81 feature flag

chore: bump version to 1.5.0

refactor: extract pure file collection logic for testability

- Split collect_input_files into pure collect_from_descriptors + I/O wrapper
- Replace 2 tempfile-based tests with 5 pure unit tests
- Add unit tests for --dry-run, --force, --quiet, --heading-offset flags
- Remove tempfile dev-dependency

Test coverage improved without filesystem access requirements.

chore: bump version to 1.3.1

feat: add --show-edits and --compact CLI options

--show-edits includes full code from TextEditGroup in fenced blocks
with syntax highlighting inferred from file extension.

--compact hides all metadata (model, agent, context, tools, timestamps)
as a convenient shorthand for minimal output.

chore: bump version to 1.2.2

refactor: FCIS testability improvements

- Extract parse_args_from(iter) for testable argument parsing
- Extract render_concat() as pure function  
- Add 8 pure unit tests for CLI argument parsing
- Remove redundant tempfile-based test
- Add Debug derives to Cli and OutputTarget
- Coverage improved: 84.4% → 86.8% lines

feat: harden CLI inputs and add tests

fix: parse symbol names from nested inlineReference.name

Inline references for symbols (functions, types) have their name inside
inlineReference.name, not at the top level. This caused empty backticks
in rendered output when referencing symbols like `Deserialize`.

chore: add CLAUDE.local.md to gitignore