docs: add cip for pfb/nonpfb limits per block

cips/cip-pfb-limits.md

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+| cip | TBD(27) |
+| - | - |
+| title | Block limits for number of PFBs and non-PFBs |
+| description | Set limits for number of PFBs and non-PFBs per block |
+| 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 limits for the number of PayForBlobs (PFBs) messages and non-PFBs messages per block. The proposal is to set the limits to 600 PFBs messages and 200 non-PFBs messages per block.
+
+## Specification
+
+1. The number of PFBs per block is limited to 600 by setting `MaxPFBMessages` to 600.
+2. The number of non-PFBs messages per block is limited to 200 by setting `MaxNonPFBMessages` to 200.
+3. These limits are soft limits implemented in the `PrepareProposal` stage.
+
+## Rationale
+
+To prevent long block times on the network by limiting the number of PFBs and non-PFBs messages per block. Limits were established based on benchmarks to achieve a target processing time of ~0.25 seconds.
+
+## Backwards Compatibility
+
+This proposal is meant to be included with v3 and the Ginger Network Upgrade. It is backwards compatible with v2.
+
+## 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).