docs: cip for tx limits

cips/cip-tx-limits.md

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+| cip | TBD(28) |
+| - | - |
+| title | Transaction size limit |
+| description | Set limit for transaction size |
+| author | Josh Stein ([@jcstein](https://github.com/jcstein)), Nina Barbakadze ([@ninabarbakadze](https://github.com/ninabarbakadze)) |
+| discussions-to | <https://forum.celestia.org/t/cip-limit-number-of-pfbs-and-non-pfbs-per-block-increase-transaction-size-limit/1843> |
+| status | Draft |
+| type | Standards Track |
+| category | Core |
+| created | 2024-10-16 |
+
+## Abstract
+
+This CIP proposes to set the limit for transaction size to 2MiB. This is a consensus-breaking change.
+
+## Specification
+
+1. Transaction size is limited to 2MiB by setting the versioned parameter `MaxTxSize` to 2097152 (2MiB in bytes).
+2. From version v3 and above, in `CheckTx`, `PrepareProposal`, and `ProcessProposal`, each transaction's size is checked against the `appconsts.MaxTxSize` threshold.
+
+## Rationale
+
+To set the transaction size limit to 2MiB, even with 8MiB blocks, to prevent issues with gossiping large transactions. Gossiping an 8MiB transaction without chunking could be detrimental to the network.
+
+## Backwards Compatibility
+
+This proposal is meant to be included with v3 and the Ginger Network Upgrade. It is a consensus-breaking change.
+
+## Security Considerations
+
+This proposal does not introduce new security risks but impacts network behavior and user experience.
+
+## Copyright
+
+Copyright and related rights waived via [CC0](https://github.com/celestiaorg/CIPs/blob/main/LICENSE).