Set fork epoch & blob schedule for Fulu (#4689)

* Move Fulu to the table of stable specifications.
* Remove "work-in-progress" notes for Fulu specifications.
* Update `FULU_FORK_EPOCH` and `BLOB_SCHEDULE`.

Values come from:

* eth-clients/mainnet#11

Author: jtraglia

README.md

@@ -27,12 +27,12 @@ ready.
 | 3    | **Capella**   | `194048`   | [Specs](specs/capella), [Tests](tests/core/pyspec/eth2spec/test/capella)     |
 | 4    | **Deneb**     | `269568`   | [Specs](specs/deneb), [Tests](tests/core/pyspec/eth2spec/test/deneb)         |
 | 5    | **Electra**   | `364032`   | [Specs](specs/electra), [Tests](tests/core/pyspec/eth2spec/test/electra)     |
+| 6    | **Fulu**      | `411392`   | [Specs](specs/fulu), [Tests](tests/core/pyspec/eth2spec/test/fulu)           |
 
 ### In-development Specifications
 
 | Seq. | Code Name | Fork Epoch | Links                                                                |
 | ---- | --------- | ---------- | -------------------------------------------------------------------- |
-| 6    | **Fulu**  | TBD        | [Specs](specs/fulu), [Tests](tests/core/pyspec/eth2spec/test/fulu)   |
 | 7    | **Gloas** | TBD        | [Specs](specs/gloas), [Tests](tests/core/pyspec/eth2spec/test/gloas) |
 
 ### Accompanying documents

configs/mainnet.yaml

@@ -54,7 +54,7 @@ ELECTRA_FORK_VERSION: 0x05000000
 ELECTRA_FORK_EPOCH: 364032  # May 7, 2025, 10:05:11am UTC
 # Fulu
 FULU_FORK_VERSION: 0x06000000
-FULU_FORK_EPOCH: 18446744073709551615  # temporary stub
+FULU_FORK_EPOCH: 411392  # December 3, 2025, 09:49:11pm UTC
 # Gloas
 GLOAS_FORK_VERSION: 0x07000000  # temporary stub
 GLOAS_FORK_EPOCH: 18446744073709551615
@@ -238,4 +238,8 @@ MAX_BYTES_PER_INCLUSION_LIST: 8192
 # Blob Scheduling
 # ---------------------------------------------------------------
 
-BLOB_SCHEDULE: []
+BLOB_SCHEDULE:
+  - EPOCH: 412672  # December 9, 2025, 02:21:11pm UTC
+    MAX_BLOBS_PER_BLOCK: 15
+  - EPOCH: 419072  # January 7, 2026, 01:01:11am UTC
+    MAX_BLOBS_PER_BLOCK: 21

specs/fulu/beacon-chain.md

@@ -1,7 +1,5 @@
 # Fulu -- The Beacon Chain
 
-*Note*: This document is a work-in-progress for researchers and implementers.
-
 <!-- mdformat-toc start --slug=github --no-anchors --maxlevel=6 --minlevel=2 -->
 
 - [Introduction](#introduction)
@@ -46,12 +44,12 @@ The epoch value in each entry MUST be greater than or equal to
 than or equal to `MAX_BLOB_COMMITMENTS_PER_BLOCK`. The blob schedule entries
 SHOULD be sorted by epoch in ascending order. The blob schedule MAY be empty.
 
-*Note*: The blob schedule is to be determined.
-
 <!-- list-of-records:blob_schedule -->
 
-| Epoch | Max Blobs Per Block | Description |
-| ----- | ------------------- | ----------- |
+|  Epoch | Max Blobs Per Block |                             Date |
+| -----: | ------------------: | -------------------------------: |
+| 412672 |                  15 | December 9, 2025, 02:21:11pm UTC |
+| 419072 |                  21 |  January 7, 2026, 01:01:11am UTC |
 
 ## Beacon chain state transition function
 

specs/fulu/das-core.md

@@ -1,7 +1,5 @@
 # Fulu -- Data Availability Sampling Core
 
-*Note*: This document is a work-in-progress for researchers and implementers.
-
 <!-- mdformat-toc start --slug=github --no-anchors --maxlevel=6 --minlevel=2 -->
 
 - [Constants](#constants)

specs/fulu/fork-choice.md

@@ -1,7 +1,5 @@
 # Fulu -- Fork Choice
 
-*Note*: This document is a work-in-progress for researchers and implementers.
-
 <!-- mdformat-toc start --slug=github --no-anchors --maxlevel=6 --minlevel=2 -->
 
 - [Introduction](#introduction)

specs/fulu/fork.md

@@ -1,7 +1,5 @@
 # Fulu -- Fork Logic
 
-*Note*: This document is a work-in-progress for researchers and implementers.
-
 <!-- mdformat-toc start --slug=github --no-anchors --maxlevel=6 --minlevel=2 -->
 
 - [Introduction](#introduction)
@@ -21,10 +19,10 @@ This document describes the process of the Fulu upgrade.
 
 Warning: this configuration is not definitive.
 
-| Name                | Value                                 |
-| ------------------- | ------------------------------------- |
-| `FULU_FORK_VERSION` | `Version('0x06000000')`               |
-| `FULU_FORK_EPOCH`   | `Epoch(18446744073709551615)` **TBD** |
+| Name                | Value                                              |
+| ------------------- | -------------------------------------------------- |
+| `FULU_FORK_VERSION` | `Version('0x06000000')`                            |
+| `FULU_FORK_EPOCH`   | `Epoch(411392)` (December 3, 2025, 09:49:11pm UTC) |
 
 #### New `initialize_proposer_lookahead`
 

specs/fulu/p2p-interface.md

@@ -1,7 +1,5 @@
 # Fulu -- Networking
 
-*Note*: This document is a work-in-progress for researchers and implementers.
-
 <!-- mdformat-toc start --slug=github --no-anchors --maxlevel=6 --minlevel=2 -->
 
 - [Introduction](#introduction)

specs/fulu/polynomial-commitments-sampling.md

@@ -1,7 +1,5 @@
 # Fulu -- Polynomial Commitments Sampling
 
-*Note*: This document is a work-in-progress for researchers and implementers.
-
 <!-- mdformat-toc start --slug=github --no-anchors --maxlevel=6 --minlevel=2 -->
 
 - [Introduction](#introduction)