Add `meta.*` category scopes (`comment`, `cosmetic`, `network`) and exception flag to Adblock TextMate grammar

[totadavid95]

Introduce three category wrapper scopes and one orthogonal exception flag into adblock.yaml-tmlanguage using begin/end blocks around existing patterns (preserving all leaf scopes), then update and extend the grammar test suite with category-aware assertions across all rule families.

Key changes:

• Replace top-level patterns with commentRules, cosmeticRules, networkRules wrappers carrying meta.<category>.adblock
• Add meta.exception.adblock for allowlist rules (@@ network, #@#/$@$ cosmetic variants)
• Add scope constants (META_COMMENT_SCOPE, META_COSMETIC_SCOPE, META_NETWORK_SCOPE, META_EXCEPTION_SCOPE)
• Update all existing test scope arrays with category scopes
• Add new category-scopes.test.ts cross-cutting suite covering every rule family + exception flag