fix: overhaul proposal selection and prioritization logic

[zhangsoledad]

What's Changed:

This PR fixes a series of logical issues in the tx-pool and block-template construction related to proposal transactions:

Prioritize proposal transactions
Proposals are now given the highest priority in the txpool.

Allow compact block recovery to use transactions from verify_queue
Compact-block reconstruction previously only searched the main pool, leading to unnecessary “missing transaction” failures when a proposal was already in verify_queue. The reconciler now checks pool_map, verify_queue, and the orphan set (when relevant).

Fix proposal selection logic in block template
The previous implementation had several severe bugs:

• Not consider to exclude proposals whose content had already been included in previous blocks (re-proposing the same data).

Related changes

• PR to update owner/repo:
• Need to cherry-pick to the release branch

Check List

Tests

• Unit test
• Integration test

Release note

Note: Add a note under the PR title in the release note.