Improve Diagnostic Source Locations and Enable Recursion Regression Coverage

[SizzleUnrlsd]

Summary

Some warnings were missing source locations (line/column), which made diagnostics less actionable and left recursion tests effectively unvalidated (no expectations found, skipping).

Problems

• NeverInitialized local variable warnings sometimes had no line/column.
• Recursion warnings (recursive or mutually recursive, unconditional self recursion) had no line/column in human output.
• The test harness parity logic could miss recursion flags when diagnostics were preceded by at line ....
• Recursion test files had no expectations, so they were skipped.

Implemented Changes

• Added robust location recovery for uninitialized local variables in src/analysis/UninitializedVarAnalysis.cpp.
• Added recursion warning locations (function-level) in src/StackUsageAnalyzer.cpp.
• Updated human-vs-JSON parity parsing in run_test.py so recursion flags are detected even when location lines are present.
• Added concrete expectations to recursion tests:
  • test/recursion/c/infinite-recursion.c
  • test/recursion/c/limited-recursion.c
  • test/recursion/cpp/infinite-recursion.cpp
  • test/recursion/cpp/limited-recursion.cpp
• Added/updated expectation for uninitialized variable location:
  • test/uninitialized-variable/uninitialized-local-argument-never-used.c

Architecture Rationale

• Kept fixes local to diagnostics production rather than changing the global debug pipeline.
• Reused existing aux.locations as the single source of truth for function-level locations.
• Used layered fallbacks for declaration recovery (debug metadata first, source-text fallback last) to improve robustness without broad side effects.

Result

• Human output now includes at line X, column Y for recursion warnings.
• Recursion tests are no longer skipped and now assert expected diagnostics.
• Full test suite passes: 157/157.

Suggested Conventional Commits

• fix(uninitialized): recover declaration line/column for never-initialized locals
• feat(recursion): add source line and column to recursion diagnostics
• test(recursion): add expectations for recursion diagnostics with locations
• fix(test-runner): detect recursion flags in human output with location-prefixed diagnostics