docs: add force inclusion user guide

[SilasZhr]

Summary

• Adds docs/user/force-inclusion.md: a step-by-step user guide explaining how to force-include a transaction on MegaETH by calling depositTransaction directly on the L1 OptimismPortal via Etherscan's Write as Proxy UI.
• Updates docs/SUMMARY.md to list the new page under the User Guide section.

Contract addresses

Network	OptimismPortal
Ethereum Mainnet	0x7f82f57F0Dd546519324392e408b01fcC7D709e8
Ethereum Sepolia	0xf68d900e1cdec64a8f5dc0ee873a9e2879256b10

Verification

• Confirmed both portal contracts are live and not paused.
• Verified depositTransaction function selector resolves to 0xe9e05c42.
• Tested on an anvil fork of Sepolia: transaction succeeded (status 0x1, gas used 92 440) and TransactionDeposited event was emitted with correct mint = 0.001 ETH and gasLimit = 100 000 encoded in opaqueData.

[claude]

Good addition — the stepper format, field table, and two-tier timing (1–2 min / 12 hr) are all clear and useful for an advanced user guide.

Four issues to fix before merging:

1. Field count wrong (line 56): table has 6 fields, text says "five" — see inline.
2. Misleading _gasLimit hint (lines 68–70): the hint incorrectly describes _gasLimit as ETH "paid upfront on L1" and implies the user's ETH value is lost on L2 failure. In OP stack, the _value ETH is minted to _to before execution, so it is delivered even if the L2 TX reverts. Only the L1 gas fee is non-refundable — see inline for a suggested rewrite.
3. Jargon in user guide (line 65): "hex-encoded calldata" — simplify per user layer rules.
4. Inconsistent address checksum (line 38): Sepolia address is all-lowercase; Mainnet address uses EIP-55 mixed-case. Use checksummed format for both.

[claude]

Nit: "100 000" uses a space as a thousands separator, which is non-standard in English. Use a comma or drop the separator.

Suggested change

	100 000 is a safe amount for a plain ETH transfer.
	100,000 is a safe amount for a plain ETH transfer.

[claude]

All four previous threads have been addressed — resolving them now.

The guide is solid: stepper structure is correct, the gasLimit/ETH accuracy fix is in place, jargon is cleaned up, and the Sepolia address now has mixed-case checksum formatting.

One remaining nit: the hint block uses "100 000" (space as thousands separator), which is non-standard English — see inline comment.

[claude]

Review

Good addition — the guide is accurate, follows the user-layer conventions (plain language, step-by-step, no unnecessary jargon), and the contract addresses and wei math all check out.

Previous threads: all four prior inline comments are resolved. ✅

One open thread remaining: the 100 000 thousands-separator issue (thread PRRT_kwDOODfgX858fHC_) — the table entry already correctly uses 100000, but the hint block still reads 100 000. Fix that and this is ready to move out of draft.