bug: coverage counts files not lines (always 1 stmt per file)

[krystophny]

Category: bug
Priority: P0

PROBLEM: Markdown and JSON reports count files, not lines; all files show Stmts=1 and overall 100% coverage regardless of actual execution.

EVIDENCE:

• Commands run:
  • fpm test --flag "-fprofile-arcs -ftest-coverage"
  • build/gfortran_*/app/fortcov --output=coverage.md
• coverage.md tail:
  | TOTAL | 249 | 249 | 100.00% | |
• Per-file rows show Stmts=1, Covered=1 for every file.
• JSON summary (coverage.json): total_lines=249, covered_lines=249; each file has only 3 line entries.

SOLUTION:

• Fix gcov parsing/aggregation to compute real executable/covered line counts.
• Add unit tests for parser; integration test on this repo to assert Stmts > 1 and totals != file count.