fix: preserve grep patterns in hook rewrites

[rathodkunj2005]

Summary

• Preserve argv token boundaries when rtk hook check / multi-arg rtk rewrite reconstruct shell commands.
• Shell-quote arguments containing metacharacters so grep alternation patterns like a|b|c are not treated as pipeline operators by the rewrite engine.
• Add regression coverage for the issue RTK parse failures in grep #880 grep patterns reported in hook rewrites.

Fixes #880.

Verification

$ cargo test --test hook_rewrite_test -- --nocapture
running 2 tests
test hook_check_preserves_grep_regex_alternation_as_one_arg ... ok
test rewrite_multi_arg_preserves_grep_regex_alternation_as_one_arg ... ok

test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

$ cargo fmt --all && cargo clippy --all-targets && cargo test --all
Finished `dev` profile [unoptimized + debuginfo] target(s) in 14.93s
Finished `test` profile [unoptimized + debuginfo] target(s) in 15.32s
test result: ok. 2429 passed; 0 failed; 8 ignored; 0 measured; 0 filtered out
test result: ok. 6 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
test result: ok. 11 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
test result: ok. 11 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
test result: ok. 2 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
test result: ok. 14 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
test result: ok. 5 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out
test result: ok. 11 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out

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