TypeScript: stop hard-ignoring source directories named coverage

[BinarySo1o]

Problem

The TypeScript language servers (typescript_language_server.py and vts_language_server.py) hard-ignore any directory named coverage in is_ignored_dirname:

return super().is_ignored_dirname(dirname) or dirname in ["node_modules", "dist", "build", "coverage"]

The intent is to skip Jest/nyc coverage-report output, but the match is on bare dirname, so it also excludes legitimate source directories named coverage (e.g. a REST resource at src/routes/coverage/). Symbol tools then fail with Cannot extract symbols for every file under such a dir, even though it is not gitignored and is_ignored_path reports it as not ignored — and there is no config hook to override is_ignored_dirname.

Fixes #1523.

Fix

Remove "coverage" from the hardcoded list in both TS servers. A real coverage-report directory is generated output and is essentially always gitignored, so gitignore already excludes it — mirroring the reasoning in #1203 (only hardcode what's universal; rely on gitignore for generated dirs).

node_modules / dist / build are intentionally left in place to keep this a single, well-scoped change.

Test

Adds test/solidlsp/typescript/test_typescript_ignored_dirs.py (mirroring test_toml_ignored_dirs.py): asserts coverage, src, lib, routes are not ignored while node_modules / dist / build / .git still are.