Add Alpha v4 release notes (#860)

* Add Alpha v4 and Alpha v4.1 release notes

* Update wording

* Fixes and addition of intro text

* Formatting fix

* Add links

* Correct typo

docs/release-notes.mdx

@@ -29,6 +29,79 @@ This release includes:
 - New arithmetization, with selected modules activated from the [Linea specification](https://github.com/Consensys/linea-specification).
 - The transition to generating traces with Besu. 
 
+## Alpha v4
+
+**Mainnet: December 10, 2024**
+
+**Linea Sepolia: November 27, 2024**
+
+This update upgrades several key contracts. Some updates prepare the protocol for the ability to 
+reconstruct the Linea state, while others add granularity to available roles, better preparing them
+for any required pauses. Many of the contract modifications have also resulted in gas optimizations.
+
+Additionally, we are deprecating the `finalizeBlocksWithoutProof` function, and adding functionality
+that enables any address to send blob submission and finalization transactions through a call 
+forwarding contract if no finalization occurs for more than six months. This effectively allows L1 
+finalization, enabling withdrawal of potentially locked funds. 
+
+- Adjust blob submission and finalization events to be state reconstruction-compatible
+  - This is a breaking change for the event structures. The new structures are below:
+  ```solidity
+  /**
+   * @notice Emitted when compressed data is being submitted and verified succesfully on L1.
+   * @dev The block range is indexed and parent shnarf included for state reconstruction simplicity.
+   * @param parentShnarf The parent shnarf for the data being submitted.
+   * @param shnarf The indexed shnarf for the data being submitted.
+   * @param finalStateRootHash The L2 state root hash that the current blob submission ends on. NB: The last blob in the collection.
+   */
+  event DataSubmittedV3(bytes32 parentShnarf, bytes32 indexed shnarf, bytes32 finalStateRootHash);
+
+  /**
+   * @notice Emitted when L2 blocks have been finalized on L1.
+   * @param startBlockNumber The indexed L2 block number indicating which block the finalization the data starts from.
+   * @param endBlockNumber The indexed L2 block number indicating which block the finalization the data ends on.
+   * @param shnarf The indexed shnarf being set as currentFinalizedShnarf in the current finalization.
+   * @param parentStateRootHash The parent L2 state root hash that the current finalization starts from.
+   * @param finalStateRootHash The L2 state root hash that the current finalization ends on.
+   */
+  event DataFinalizedV3(
+    uint256 indexed startBlockNumber,
+    uint256 indexed endBlockNumber,
+    bytes32 indexed shnarf,
+    bytes32 parentStateRootHash,
+    bytes32 finalStateRootHash
+  );
+  ```
+  - `DataSubmittedV2` becomes `DataSubmittedV3`, `DataFinalized` becomes `DataFinalizedV3`
+  (`DataFinalizedV2` was skipped to align version numbers).
+  - The change also introduced gas optimizations for blob submission and finalization. 
+- Create granular roles for contracts `LineaRollup`, `L2MessageService` and `TokenBridge`:
+  - `LineaRollup`: Introduce more granular pausing and an additional verifier unsetting role 
+  - `L2MessageService`: Introduce more granular pausing
+  - `TokenBridge`: Previously all administration functions were managed by a single owner (multisig) 
+  role. The update adds role-based access with more granular roles per function, particularly for 
+  pausing.
+- Remove `finalizeBlocksWithoutProof` function
+  - The function enabled finalization without proofs. This allowed network activity to continue 
+  while fundamental changes, such as changing the state management hashing mechanism, were being 
+  made. This is the only time the function was used, and it was primarily retained as a contingency.
+- Allow any address to finalize blocks if no finalization has occurred in the last six months
+  - Add functionality to the `LineaRollup` contract to allow any address to submit valid blobs and 
+  valid finalization proofs, generated by running the Linea stack locally, to withdraw funds from 
+  L2. The mechanism only works if no finalization has happened for six months. The system is 
+  intended as a contingency. 
+  - The change enables the `LineaRollup` contract to grant a "fallback operator" the `OPERATOR_ROLE` 
+  required to submit the blobs and finalization proofs. The "fallback operator" is a message 
+  forwarding contract enabling any address to submit this data.
+- Bump L1 Solidity version to v0.8.26. Introduces slight gas optimizations.
+- Optimize message and new token creation hashing, making it slightly cheaper to send and claim 
+messages.
+- Address non-critical findings from previous audit rounds:
+  - [Cyfrin](https://github.com/Cyfrin/cyfrin-audit-reports/blob/main/reports/2024-11-28-cyfrin-linea-v2.0.pdf)
+  - Diligence (ongoing)
+  - [OpenZeppelin](https://blog.openzeppelin.com/linearollup-and-tokenbridge-role-upgrade)
+- Generally clean up error management and interfaces.
+
 ## Alpha v3.6 
 
 ### Block size changes