feat: treat kcl.mod file as a compile unit

[Peefy]

1. Does this PR affect any open issues?(Y/N) and add issue references (e.g. "fix #123", "re #123".):

• N
• Y

feat: treat kcl.mod file as a compile unit

2. What is the scope of this PR (e.g. component or file name):

• feat: treat kcl.mod file as a compile unit
• kclvm/config/src/modfile.rs
• kclvm/config/src/vfs.rs
• kclvm/driver/src/lib.rs

3. Provide a description of the PR(e.g. more details, effects, motivations or doc link):

• Affects user behaviors
• Contains syntax changes
• Contains variable changes
• Contains experimental features
• Performance regression: Consumes more CPU
• Performance regression: Consumes more Memory
• Other

4. Are there any breaking changes?(Y/N) and describe the breaking changes(e.g. more details, motivations or doc link):

• N
• Y

5. Are there test cases for these changes?(Y/N) select and add more details, references or doc links:

• Unit test
• Integration test
• Benchmark (add benchmark stats below)
• Manual test (add detailed scripts or steps below)
• Other

• kclvm/config/src/testdata/kcl.mod

[He1pa]

LGTM

[coveralls]

Pull Request Test Coverage Report for Build 9188605121

Details

• 81 of 102 (79.41%) changed or added relevant lines in 3 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.009%) to 71.082%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
kclvm/config/src/modfile.rs	51	57	89.47%
kclvm/driver/src/lib.rs	24	39	61.54%

Files with Coverage Reduction	New Missed Lines	%
kclvm/config/src/modfile.rs	1	93.67%

Totals
Change from base Build 9177105510:	-0.009%
Covered Lines:	53860
Relevant Lines:	75772

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💛 - Coveralls

[zong-zhe]

LGTM