HIGH_SIGNAL_PATH_CANDIDATES is JS/TS-centric

[fazxes]

Context

From PR #13 code review.

Problem

HIGH_SIGNAL_PATH_CANDIDATES in nightshift/constants.py lines 99-114 only lists JS/TS project paths:

HIGH_SIGNAL_PATH_CANDIDATES = [
    "src/lib/auth",
    "src/lib/http.ts",
    "src/app/api",
    "src/lib/db/queries",
    ...
]

This works for the current target repos (JS/TS), but if Nightshift is used against Python, Go, Rust, or other language repos, none of these paths will match and the focus hints feature becomes a no-op.

Suggested fix

This is low priority since the current target is JS repos. When multi-language support is needed, consider:

• Making the candidates configurable via .nightshift.json (e.g. a focus_paths config key)
• Adding language-detection logic to select from language-specific candidate lists
• Or simply adding common patterns for other ecosystems (e.g. app/models, internal/auth, pkg/api, src/main)