chore: archive legacy task history

[0xth4nh]

What Changed

This PR is Phase 1 of the contract-deployments reorg: archive legacy task history.

• Moves the existing top-level task history for mainnet, sepolia, sepolia-alpha, zeronet, and solana into archive/legacy/<network>.
• Preserves prior task files, records, validations, signatures, and configs unchanged. This is a path-only archival move.
• Clears the old active root task paths so future signer discovery can be pointed at a new active layout without traversing legacy history.

Why

All smart contract ops tasks have historically lived directly under network-specific root folders. That has worked, but it has also left all executed historical tasks on the active path and created duplicated task structure across networks.

Archiving the legacy folders reduces active-path noise while preserving the full historical record in git and in archive/legacy.

What This PR Does Not Do

• Does not add the new active/evm layout.
• Does not move current network config into active/evm/config/<network>.
• Does not change signer-tool discovery yet.
• Does not reorganize reusable scripts into active/evm/script/common/<category>.
• Does not remove setup templates or add archival workflow tooling.

What Next

1. Phase 2: Active layout

   • Add active/evm.
   • Move current network config into active/evm/config/<network>.
   • Teach the signer tool to discover validations and signatures from the new layout.

2. Phase 3: Script and signer-tool reorg validation

   • Move reusable scripts into active/evm/script/common/<category>.
   • Remove the old setup-template surface.
   • Prove the signer UI still works against the reorganized task layout.
   • Patch signer-tool state-diff behavior.
   • For the demo branch only, temporarily skip task-origin validation and pin a historical fork block for the already-executed mainnet task.

3. Phase 4: Archival workflow

   • Build tooling and docs for moving completed tasks from active/evm into archive/.
   • Clean up the staging branch after the demo by removing the mainnet skipTaskOriginValidation, removing --fork-block-number 25347661, regenerating real task-origin signatures, and keeping only production-ready changes.

Testing

• Not run; path-only archival move.
• Verified no tracked files remain under the old top-level task roots.
• Verified archived task history now lives under archive/legacy/.

[cb-heimdall]

✅ Heimdall Review Status

Requirement	Status	More Info
Reviews	✅ 2/2	Denominator calculation Show calculation 1 if user is bot 0 1 if user is external 0 2 if repo is sensitive 0 From .codeflow.yml 2 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 2 2 1 if commit is unverified 0 Sum 2

[jackchuma]

LGTM - please hold off on merging this until after the task signer tool is ready

Approved review 4638121224 from jackchuma is now dismissed due to new commit. Re-request for approval.