Remove unused constants, instance variables, and methods

- INDENT_CODE_OFFSET, DIRECTIVE_ELSE_RE, CONTINUATION_DIRECTIVE_RE
- @class_name in both converters
- convert_entry_signature in MarkdownToRRD

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: znz

lib/bitclust/markdown_to_rrd.rb

@@ -16,7 +16,6 @@ def convert
       @lines = @src.lines
       @out = []
       @index = 0
-      @class_name = nil
       @front_matter = {}
 
       parse_front_matter
@@ -302,11 +301,6 @@ def convert_h4_heading(line)
       convert_heading_with_anchor(line, '====')
     end
 
-    def convert_entry_signature(line)
-      @out << line.sub(/\A### /, '--- ')
-      advance
-    end
-
     def strip_code_span(text)
       text.sub(/\A`(.+)`\z/, '\\1')
     end
@@ -425,9 +419,6 @@ def convert_h2(line)
     end
 
     def convert_h1(line)
-      if line =~ /\A# (?:class|module|object|reopen|redefine)\s+(\S+)/
-        @class_name = $1
-      end
       @out << line.sub(/\A# /, '= ')
       advance
     end

lib/bitclust/rrd_to_markdown.rb

@@ -2,8 +2,6 @@
 
 module BitClust
   class RRDToMarkdown
-    INDENT_CODE_OFFSET = 3
-
     def self.convert(rrd)
       new(rrd).convert
     end
@@ -16,7 +14,6 @@ def convert
       @lines = @src.lines
       @out = []
       @index = 0
-      @class_name = nil
       @front_matter = {}
       @current_section = nil
 
@@ -163,7 +160,6 @@ def convert_emlist(line)
     end
 
     DIRECTIVE_NEST_RE = /\A\#@(?:since|until|if)\b/
-    DIRECTIVE_ELSE_RE = /\A\#@else\s*$/
     DIRECTIVE_END_RE = /\A\#@end\s*$/
 
     def convert_samplecode(line)
@@ -255,8 +251,6 @@ def convert_see(line)
       collect_continuation_lines
     end
 
-    CONTINUATION_DIRECTIVE_RE = /\A\#@(?:since|until|if|else|end)\b/
-
     def collect_continuation_lines
       nest = 0
       while @index < @lines.length
@@ -407,9 +401,6 @@ def convert_indented_code(line)
     end
 
     def convert_h1(line)
-      if line =~ /\A= (?:class|module|object|reopen|redefine)\s+(\S+)/
-        @class_name = $1
-      end
       @out << line.sub(/\A= /, '# ')
       advance
       # include/extend/alias はパススルー（front matter にしない）