Add automated extension-to-language mapping tests for all new grammars
that have file extensions. Removes conflicting extensions:
- .blade.php: compound extension, handled by userconfig system
- .env*: filenames, not extensions (no auto-discovery for dotfiles)
- .sv/.svh: already mapped to Verilog, SystemVerilog uses same grammar
Enforce WarningsAsErrors: '*' with zero suppressions of entire check categories.
All non-FP warnings fixed at source; true false positives get per-instance NOLINT
with reasoning. Fixes include: braces around statements (1679), isolate declarations
(75), explicit casts for multilevel pointer conversions, missing includes, function
parameter documentation via NOLINT, and proper NOLINTBEGIN/NOLINTEND nesting.
Complete C implementation of the indexing pipeline (src/), parallel worker
pool, graph buffer with merge support, SQLite writer, and 1893-test suite.
Linter setup: zero warnings from clang-tidy (all checks enabled, no NOLINT
suppressions), cppcheck, and clang-format. All issues fixed at source —
proper headers for external linkage, GROW_ARRAY macro restructured to
eliminate type parameter, null-deref paths guarded, named intermediates
for suspicious-argument checks.