Fix identified issues and improve stability

[tamada]

Addressing several points raised during code review:

• Fix potential panics (unwrap calls)
• Improve Error display with newlines
• Correct prologue loading from output destination
• Refactor CLI to avoid redundant config writes
• Simplify internal file reading

[coveralls]

Coverage Report for CI Build 26801786528

Coverage increased (+0.4%) to 60.809%

Details

• Coverage increased (+0.4%) from the base build.
• Patch coverage: 29 uncovered changes across 3 files (29 of 58 lines covered, 50.0%).
• 10 coverage regressions across 2 files.

Uncovered Changes

File	Changed	Covered	%
lib/src/lib.rs	36	18	50.0%
cli/src/main.rs	10	0	0.0%
lib/src/routine.rs	8	7	87.5%
Total (5 files)	58	29	50.0%

Coverage Regressions

10 previously-covered lines in 2 files lost coverage.

File	Lines Losing Coverage	Coverage
lib/src/lib.rs	9	65.98%
lib/src/routine.rs	1	86.29%

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Coverage Stats

Relevant Lines:	1286
Covered Lines:	782
Line Coverage:	60.81%
Coverage Strength:	114.18 hits per line

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💛 - Coveralls