Backport release/v6.6: Update v6.6 change log in prep to cut v6.6.2 patch

[seidroid]

Backport of #3964 to release/v6.6.

[cursor]

PR Summary

Low Risk
Documentation-only changelog edit with no application, CI, or release-artifact logic changes.

Overview
Backport of the main-branch changelog refresh (#3964) onto release/v6.6, ahead of cutting v6.6.2.

CHANGELOG.md gains nine new bullets at the top of the v6.6 sei-chain list (newest first), documenting backports and release prep since the prior changelog update: SS DB context cancellation (#3957), default Sei Labs bootstrap seeds (#3954), Codex review tolerance (#3951), configurable inbound P2P accept rate (#3939), go-releaser experimental notice (#3880), v6.6.1 version bump (#3878), prior changelog update (#3877), LCD pagination with v6.6 precompile semantics (#3873), and redundant libstdc++6 install removal (#3848). No runtime or build behavior changes in this PR—documentation only.

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[github-actions]

The latest Buf updates on your PR. Results from workflow Buf / buf (pull_request).

Build	Format	Lint	Breaking	Updated (UTC)
✅ passed	✅ passed	✅ passed	✅ passed	Aug 19, 2026, 5:48 PM

[masih]

only changelog update; escalating to fast merge.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 58.15%. Comparing base (f8aad07) to head (63c8ad6).
⚠️ Report is 1 commits behind head on release/v6.6.

Additional details and impacted files

@@               Coverage Diff                @@
##           release/v6.6    #3965      +/-   ##
================================================
- Coverage         59.02%   58.15%   -0.87%     
================================================
  Files              2226     2152      -74     
  Lines            183783   175189    -8594     
================================================
- Hits             108479   101883    -6596     
+ Misses            65553    64256    -1297     
+ Partials           9751     9050     -701     

Flag	Coverage Δ
sei-db	69.80% <ø> (ø)
sei-db-state-db	?

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see 74 files with indirect coverage changes

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