Inline directives in Ruby, Rust, Java, C# and other languages are silently ignored #7

Summary

Only JS/TS, Python, Go and shell files are lexed (src/lexer.rs, Language::from_path). @openshell comments in any other language (Ruby, Rust, Java, C#, Kotlin, PHP, ...) are ignored with no warning.

Steps to reproduce

1. Create a.rb:

   # @openshell egress api.x.com:443 reason="r" bin=/usr/bin/ruby
   Net::HTTP.get(URI("https://api.x.com/"))

2. openshell-annotate scan .
3. openshell-annotate generate . and openshell-annotate lint .

Seen with real projects: pocketrb (Ruby) and anthropic-proxy-rs (Rust).

Expected

• A warning when a repo contains many source files in languages that are not scanned (for example "12 .rb files not scanned").
• A way to declare the comment leader for extra extensions, for example [languages.extra] rb = "hash" (#) or rs = "slash" (//), so Ruby and Rust inline directives work.

Actual

scan says 0 directive(s), generate only warns policy is empty, lint reports nothing for the .rb file.

Notes

• A .sh sidecar file with the directives works today and should be documented as the recommended workaround.
• A first-class sidecar file (openshell.annotations.yaml) is tracked separately as a follow-up.

Found while testing five real projects (see the local candidate report). Numbered #1 in that report.