Remove deprecated MegaethTestnet network

[DZakh]

Removes the deprecated MegaethTestnet (chain ID 6342) network configuration in favor of MegaethTestnet2 (chain ID 6343).

Changes:

• Removed MegaethTestnet enum variant from the Network enum
• Removed MegaethTestnet from the network matching logic in the impl Network block

The MegaethTestnet2 variant remains as the active testnet configuration for Megaeth.

https://claude.ai/code/session_018sUFaG1runepaMNvFoRGB7

Summary by CodeRabbit

• Chores
  • Network configuration updated: "Megaeth Testnet" replaced with "Megaeth Testnet 2" and related chain behavior adjusted.
• Documentation
  • CLI help updated: removed the old "megaeth-testnet" option from the list of supported blockchains.

[coderabbitai]

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 8b91439f-0567-489b-8d2c-cd958a15457f

📥 Commits

Reviewing files that changed from the base of the PR and between de15d98 and 0b9760c.

📒 Files selected for processing (1)

• packages/cli/CommandLineHelp.md

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📝 Walkthrough

Walkthrough

Replaces Network::MegaethTestnet (6342) with Network::MegaethTestnet2 (6343) in the enum and updates the get_max_reorg_depth match arms; removes megaeth-testnet from the CLI --blockchain documented values.

Changes

Network Chain Identifier Update

Layer / File(s)	Summary
Update Network enum variant and reorg depth mapping packages/cli/src/config_parsing/chain_helpers.rs, packages/cli/CommandLineHelp.md	Network::MegaethTestnet (u64 6342) is replaced with Network::MegaethTestnet2 (u64 6343); get_max_reorg_depth match arm now references MegaethTestnet2; CLI help removes megaeth-testnet from the --blockchain options.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'Remove deprecated MegaethTestnet network' accurately and concisely describes the main change in the pull request: removing the deprecated MegaethTestnet variant.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@packages/cli/CommandLineHelp.md`:
- Line 383: The markdown heading "###### **Subcommands:**" at Line 383 jumps
from the higher "##" section and violates MD001; change its level to the next
valid heading level (e.g., "### **Subcommands:**") so it follows the existing
"##" section hierarchy and keeps the document structure consistent.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 8b91439f-0567-489b-8d2c-cd958a15457f

📥 Commits

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• packages/cli/CommandLineHelp.md

[coderabbitai]

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Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@packages/cli/CommandLineHelp.md`:
- Line 383: The markdown heading "###### **Subcommands:**" at Line 383 jumps
from the higher "##" section and violates MD001; change its level to the next
valid heading level (e.g., "### **Subcommands:**") so it follows the existing
"##" section hierarchy and keeps the document structure consistent.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 8b91439f-0567-489b-8d2c-cd958a15457f

📥 Commits

Reviewing files that changed from the base of the PR and between de15d98 and 0b9760c.

📒 Files selected for processing (1)

• packages/cli/CommandLineHelp.md

🛑 Comments failed to post (1)

packages/cli/CommandLineHelp.md (1)

383-383: ⚠️ Potential issue | 🟡 Minor | ⚡ Quick win

Fix heading-level jump at Line 383 (MD001).

###### **Subcommands:** skips heading levels after the ## section and triggers markdownlint. Use the next valid heading level to satisfy lint and keep structure consistent.

🧰 Tools

🪛 markdownlint-cli2 (0.22.1)

[warning] 383-383: Heading levels should only increment by one level at a time
Expected: h3; Actual: h6

(MD001, heading-increment)

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@packages/cli/CommandLineHelp.md` at line 383, The markdown heading "######
**Subcommands:**" at Line 383 jumps from the higher "##" section and violates
MD001; change its level to the next valid heading level (e.g., "###
**Subcommands:**") so it follows the existing "##" section hierarchy and keeps
the document structure consistent.