feat: add line-by-line mode as default, stream without loading files …

…into memory (chmln#328)

* refactor: remove pub(crate)

This made no sense because we don't intend to ever release `sd` as a crate

* remove old feature

* address clippy lints and improve code quality

* refactor: split sd and sd-cli

* feat: add --line-by-line (-L) flag for line-by-line processing

Add a new processing mode that handles input line by line instead of
reading entire files into memory. This fixes several long-standing issues:
- OOM on large files (O(line_size) memory instead of O(file_size))
- stdin waits for EOF (output now flushed per line, enables streaming)
- `^` matches phantom empty line after trailing `\n`
- `\s+$` eats newlines because `\s` sees `\n` across line boundaries

The implementation strips `\n` before passing each line to the replacer,
then restores it, so regex never sees newline characters. Files without
trailing newlines are preserved as-is. In-place file modification uses
the same atomic temp-file-and-rename pattern as the existing code path.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* feat: make line-by-line the default, add --across (-A) for whole-file

Line-by-line processing is now the default behavior. This provides
better defaults for common use cases: lower memory usage, streaming
stdin output, and predictable regex anchor behavior.

For patterns that need to match across line boundaries (e.g. replacing
\n or multi-line patterns), use the new --across / -A flag which
restores the previous whole-file behavior.

Pre-validates all input files before modifying any, matching the
atomicity guarantees of the mmap-based code path.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* docs: add line-by-line vs across benchmarks to README

Add benchmark results comparing line-by-line (default) and across (-A)
modes on a 1M line (~36MB) test file:
- Line-by-line is ~2-3x slower than across mode for throughput
- Still faster than sed for regex replacements
- Memory usage: 3 MB (line-by-line) vs 74 MB (across)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* perf: optimize line-by-line mode with chunked reading

Replace per-line read_until() calls with chunked reading (8KB chunks)
and a line buffer that spans chunk boundaries. This reduces syscall
overhead and improves CPU cache locality.

Benchmark results on 1M line file (~36MB):
- Before: 357ms (2.84x slower than across mode, slower than sed)
- After:  106ms (3.19x slower than across mode, 1.1x faster than sed)

The trade-off between modes is:
- Across mode: fastest (33ms), uses more memory (~74MB)
- Line-by-line: now much faster (106ms), bounded memory usage
- Line-by-line still respects memory limits for streaming use cases

fix build, tests, and lint regressions

remove file-mapping code paths and dependency

Prepare 1.0.0 release (chmln#277)

* Bump version to v1.0.0

* `cargo xtask gen`

* Add all new entries to the changelog

1.0.0-beta.0 release

Error on `$<num><non_num>` capture replacement names (chmln#258)

* Mostly working capture name validation

* Improve inputs for property tests

* Fix advancing when passing over escaped dollar signs

* Switch to inline snapshot captures

* Cleanup invalid capture error formatting code

Error on `$<num><non_num>` capture replacement names (chmln#258)

* Mostly working capture name validation

* Improve inputs for property tests

* Fix advancing when passing over escaped dollar signs

* Switch to inline snapshot captures

* Cleanup invalid capture error formatting code

(cargo-release) sd version 0.7.6

(cargo-release) sd version 0.7.4

(cargo-release) sd version 0.7.2