docs: improve grammar and terminology consistency in Building on Scroll

[airope]

Closes #550

Improves grammar and terminology consistency across the Building on Scroll documentation section:

building-on-scroll.mdx:

• Hyphenated "zero-knowledge" consistently (was "zero knowledge")
• Removed incorrect article ("the Scroll" → "Scroll")
• Removed unnecessary comma in heading
• Standardized L1/L2 terminology (was mixing "Layer 1"/"Layer 2" with "L1"/"L2")

index.mdx:

• Fixed typo: "trough" → "through"
• Fixed capitalization: "can i" → "can I"
• Improved question phrasing for FAQ consistency
• Added inline code formatting for CLI flags

ethereum-and-scroll-differences.mdx:

• Fixed footnote typo: "willadpot" → "willadopt"
• Added missing comma in precompiles list
• Added missing space before parenthetical
• Fixed semicolon usage before "however"
• Removed trailing whitespace

developer-ecosystem.mdx:

• Fixed typo: "pereference" → "preference"
• Fixed typo: "accesibility" → "accessibility"
• Fixed typo: "Compund" → "Compound" (2 occurrences)

estimating-gas-and-tx-fees.mdx:

• Fixed subject-verb agreement: "all transaction incurs" → "all transactions incur"

transaction-fees-on-scroll.mdx:

• Removed trailing space in frontmatter
• Improved phrasing: "1-by-1" → "one by one"

erc1155-token-bridge.mdx:

• Fixed contraction: "you're transaction" → "your transaction"

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