[30.x] Backports & rc3 #33473

1. 
   fanquake commented at 2:11 pm on September 24, 2025: member

   Backports:

   • #33446
   • #33475
2. test: add block 2016 to mock mainnet

   The next commit requires an additional mainnet block which changes the difficulty.
   
   Also fix a few minor mistakes in the test (suite):
   - rename the create_coinbase retarger_period argument to halving_period. Before bitcoin#31583 this was hardcoded for regtest where these values are the same.
   - drop unused fees argument from mine helper
   
   Finally the CPU miner instructions for generating the alternative mainnet chain are expanded.
   
   Github-Pull: #33446
   Rebased-From: 4c3c1f42cf705e039751395799240da33ca969bd

   4ec30d53ec
3. rpc: fix getblock(header) returns target for tip

   A target field was added to the getblock and getblockheader RPC calls in bitcoin#31583, but it mistakingly always used the tip value.
   
   Because regtest does not have difficulty adjustment, a test is added for mainnet instead.
   
   Github-Pull: #33446
   Rebased-From: bf7996cbc3becf329d8b1cd2f1007fec9b3a3188

   1e348bc55a
4. fanquake added this to the milestone 30.0 on Sep 24, 2025
5. DrahtBot added the label Backport on Sep 24, 2025
6. 
   DrahtBot commented at 2:11 pm on September 24, 2025: contributor

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/33473.

   Reviews

   See the guideline for information on the review process. A summary of reviews will appear here.

7. miner: fix `addPackageTxs` unsigned integer overflow

   Github-Pull: #33475
   Rebased-From: b807dfcdc5929c314d43b790c9e705d5bf0a86e8

   45703931e5

Contributors
fanquake DrahtBot

Labels
Backport

Milestone
30.0