Add scoped per-rule ignore markers to Obsidian Linter

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What this task asks for

Implement standalone comment markers that disable and re-enable specific lint rules with nested scope handling. The linter must recognize both HTML comment markers and Obsidian comment markers. Markers that occur inside YAML frontmatter, fenced or indented code blocks, inline code, or math blocks must be ignored. Marker lines must never be modified by any rule, regardless of whether the marker disables that rule. `N` must be a positive base-10 integer, otherwise the marker has no effect. Rule lists must be normalized case-insensitively, with duplicates removed, and trailing commas / empty entries ignored. Disabling all rules and re-enabling specific rules within that scope must be supported.