add beryl, b20 docs, activation timelines

[roethke]

What changed? Why?

Adds the Beryl hardfork specification section to base-chain/specs/upgrades, covering the three main deliverables:

• B20 (beryl/b20.mdx) - full spec for the native token standard: Rust precompile architecture, roles model, policy scopes, mint/burn paths, supply cap, memos, granular pause, ERC-2612/ERC-7572, Asset and Stablecoin variants, and the roadmap (gas payment, virtual addresses, indexed data, perf targets)
• Withdrawals (beryl/overview.mdx) - documents the single-proof finalization window reduction from 7 to 5 days, with the dual-proof fast path remaining at 1 day
• Reth V2 (beryl/reth-v2.mdx) - Storage V2 disk reductions (up to 50%), rewritten state root pipeline (sparse-trie caching, parallel trie, Proof V2), and published benchmarks (+33% throughput, ~25% lower latency)
• Activation timestamps

Notes to reviewers

How has it been tested?
Locally

[cb-heimdall]

✅ Heimdall Review Status

Requirement	Status	More Info
Reviews	✅ 1/1	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 1 Additional review requirements Show calculation Max 0 0 From CODEOWNERS 0 Global minimum 0 Max 1 1 1 if commit is unverified 0 Sum 1

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[ilikesymmetry]

Looks great, thanks for aggregating content across base-std and blog. Happy to make any tweaks needed next week after getting this in node providers hands tomorrow :)

[luis200412]

Cool Sent from Yahoo Mail for iPhone On Thursday, June 11, 2026, 5:44 PM, Conner Swenberg ***@***.***> wrote: @ilikesymmetry approved this pull request. Looks great, thanks for aggregating content across base-std and blog. Happy to make any tweaks needed next week after getting this in node providers hands tomorrow :) — Reply to this email directly, view it on GitHub, or unsubscribe. Triage notifications, keep track of coding agent tasks and review pull requests on the go with GitHub Mobile for iOS and Android. Download it today! You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

Approved review 4481343017 from ilikesymmetry is now dismissed due to new commit. Re-request for approval.