feat(docs-site): add scenario and explanation for contestable rollup

packages/docs-site/src/content/docs/core-concepts/contestable-rollups.md

@@ -3,6 +3,25 @@ title: Contestable rollups
 description: Core concept page for "Contestable rollups".
 ---
 
-The current Taiko mainnet and testnet are both configured as a based contestable rollup (BCR).
+## Based Contestable Rollup
+
+In based rollups, block building is permissionless. But permissionless block building comes at a cost, in the form of permissionless attacks to the chain if there is a vulnerability in the Taiko codebase. Centralized rollups can tolerate these risks due to their centralized nature, but Taiko cannot as fully decentralized design. Therefore, Taiko needs a robust multi-proof structure to prevent malicious behaviours.
+
+Taiko is configured as a based contestable rollup (BCR). This means that there is a hierarchy of proofs in Taiko and it's permissionless to contest all tiers of proofs. Currently Taiko has SGX as a TEE proof, RiscO(RiscZero) and SP1(Succinct) as ZK proofs, Guardian (multi-sig) proof which is owned by Taiko Labs. Guardian proof is not contestable and we plan to phase out after the next protocol hard fork.
+
+![Proof Tiers](~/assets/content/docs/core-concepts/proof-tiers.png)
+
+**Scenario:**
+
+The process begins when a proposer submits a new block, followed by a tier-1 (SGX) prover who submits a proof with a TAIKO bond. During the 4 hour cooldown period, anyone can contest this proof by posting their own bond, as demonstrated by Cindy.
+
+The system then supports two possible scenarios: If a higher-tier proof confirms the original proof was correct, the original prover receives back their bond plus a reward, while the contester loses their bond. Conversely, if the higher-tier proof shows the original was wrong, the contester receives back their bond plus a reward, and the original prover loses their stake.
+
+If the contester wins: The contester receives their contestation bond back plus 1/4 of the original prover's validity bond. The new prover receives 1/4 of the original prover's validity bond as a proving fee. The remaining 1/2 goes to the DAO treasury.
+
+If the original prover wins: The original prover reclaims their validity bond and receives 1/4 of the contestation bond as a reward. The new prover (who may be the original prover) earns 1/4 of the contestation bond. The remaining 1/2 goes to the DAO treasury.
+
+![BCR Workflow](~/assets/content/docs/core-concepts/contestable.png)
+
 
 Check out our blog post on the [Based Contestable Rollup (BCR): A configurable, multi-proof rollup design](https://taiko.mirror.xyz/Z4I5ZhreGkyfdaL5I9P0Rj0DNX4zaWFmcws-0CVMJ2A).