test: add tests for bash-file-extract utility

[George-iam]

The bash file extraction utility (src/utils/bash-file-extract.ts) parses bash commands to extract file paths that a command writes to (redirects, tee, sed -i, cp, mv, rm, touch, etc.). While the existing test suite covers some related functionality, the extractBashWritePaths function itself could use more edge-case coverage. It is a pure function that takes a command string and returns an array of paths, making it straightforward to test.

Relevant files:

• src/utils/bash-file-extract.ts — the module to test (exports extractBashWritePaths)
• test/ — place the new test file here as bash-file-extract.test.ts

Suggested test cases:

• Simple redirect: echo hello > out.txt
• Append redirect: echo hello >> log.txt
• Stderr redirect: cmd 2> error.log
• Combined redirect: cmd &> all.log
• Tee: cmd | tee output.txt
• Tee with -a flag: cmd | tee -a output.txt
• Compound commands: echo a > x.txt && echo b > y.txt
• Filtering of pseudo-paths: /dev/null, -, $VAR
• cp/mv destination extraction
• Quoted paths: echo hello > "my file.txt"
• No false positives from plain commands: ls -la, echo hello

Acceptance criteria:

• New file test/bash-file-extract.test.ts with at least 12 tests
• All tests pass with npm test