Update v6.6 changelog in prep to cut rc4

[bdchatham]

Adds the v6.6 changelog entries for the changes landed on release/v6.6 since the rc3 changelog update (#3744):

• Backport release/v6.6: fix(giga): route EVM validation failures to v2 fallback (CON-368) #3757 — Backport of the CON-368 fix (route EVM validation failures to v2 fallback)
• Bump version in prep to release v6.6-rc3 #3748 — the rc3 version bump

Lands on main first per the release runbook; the backport release/v6.6 label auto-opens the backport into the release branch.

Prep for cutting v6.6.0-rc4. Docs-only; no code change.

🤖 Generated with Claude Code

[cursor]

PR Summary

Low Risk
Docs-only changelog edits with no code, config, or state-machine impact.

Overview
Updates CHANGELOG.md under v6.6 so the release notes match work landed on release/v6.6 since the rc3 changelog update.

New entries document #3781 (giga falls back to v2 on execution errors), #3766 (rc4 version bump), #3757 (EVM validation failures routed to v2 fallback, CON-368), #3748 (rc3 version bump), and #3746 (rc3 changelog update). The existing #3731 line is normalized from “RC2” to “rc2” for consistent casing.

This is documentation only—no runtime or consensus behavior changes in this PR; it prepares cutting v6.6.0-rc4.

^{Reviewed by Cursor Bugbot for commit 6fd9d3a. Bugbot is set up for automated code reviews on this repo. Configure here.}

[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	Jul 20, 2026, 5:51 PM

[seidroid]

Docs-only PR adding two v6.6 changelog entries. Both entries (#3757 and #3748) exactly match the referenced PRs' titles and are placed in correct descending PR-number order at the top of the v6.6 section. No code changes and nothing of concern.

Findings: 0 blocking | 2 non-blocking | 0 posted inline

Blockers

• None at the file/PR level.

Non-blocking

• The Cursor second-opinion review file (cursor-review.md) is empty — that pass produced no output. The Codex review reported no material issues.
• Verified the two added changelog lines match the actual GitHub titles of PR #3757 ("Backport release/v6.6: fix(giga): route EVM validation failures to v2 fallback (CON-368)") and PR #3748 ("Bump version in prep to release v6.6-rc3"), and that ordering is correct.

[claude]

LGTM — docs-only changelog update, entries match the referenced PRs (#3757, #3748) and the version-ordering convention used by prior rc changelog entries.

What was reviewed: Confirmed the two new lines reference real, already-merged PRs (#3757 backport of CON-368, #3748 rc3 version bump) and are inserted in the correct chronological position at the top of the v6.6 section. No code, config, or logic changes in this PR.

Extended reasoning...

Overview

Single-file change to CHANGELOG.md adding two entries to the v6.6 section, documenting PR #3757 (backport of the CON-368 EVM validation fallback fix) and #3748 (rc3 version bump). This is prep work for cutting v6.6.0-rc4 and lands on main first before being backported to release/v6.6 via the label.

Security risks

None. This is a documentation-only change with no code, configuration, or build logic affected.

Level of scrutiny

Minimal scrutiny is appropriate here — it's a two-line addition to a markdown changelog file, following an established pattern from prior rc changelog PRs (rc2, rc3) visible in the same file. There is no ambiguity or design decision involved.

Other factors

No prior review from me exists on this PR. The referenced PR numbers correspond to real, already-merged changes (confirmed via recent commit history: CON-368 fix commit 65411b1 is in the log). No outstanding review comments to address.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 58.95%. Comparing base (91a5db4) to head (6fd9d3a).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #3765      +/-   ##
==========================================
- Coverage   60.15%   58.95%   -1.20%     
==========================================
  Files        2302     2201     -101     
  Lines      192091   180049   -12042     
==========================================
- Hits       115552   106154    -9398     
+ Misses      66216    64552    -1664     
+ Partials    10323     9343     -980     

Flag	Coverage Δ
sei-db	70.41% <ø> (ø)
sei-db-state-db	?

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see 162 files with indirect coverage changes

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[masih]

These should be opened against the release branch, not main :); otherwise it would end up tagging main. Closing. oh this is changelog only; my bad never mind.

[seidroid]

Docs-only PR adding two v6.6 changelog entries (#3757 and #3748) in prep for cutting rc4. The diff is exactly two added lines, correctly placed under the v6.6 section, well-formed, and matching the existing entry style. No code changes and nothing of concern.

Findings: 0 blocking | 2 non-blocking | 0 posted inline

Blockers

• None at the file/PR level.

Non-blocking

• Cursor's review file (cursor-review.md) was empty — that second-opinion pass produced no output. Codex reported no material issues, which matches this review.
• Minor: entries are ordered #3757 then #3748 (descending PR number, matching the existing descending convention in the section), so no change needed — just noting the ordering is consistent with surrounding lines.

[claude]

LGTM — docs-only changelog update, no code changes.

Extended reasoning...

Overview

This PR only modifies CHANGELOG.md, adding two entries to the v6.6 section (#3757 backport summary, #3748 rc3 version bump) ahead of cutting v6.6.0-rc4. No source code, config, or build files are touched.

Security risks

None. Changelog text has no execution path or security surface.

Level of scrutiny

Minimal scrutiny is appropriate here — this is a mechanical, non-functional documentation change following an established release-prep pattern seen in prior PRs (e.g. #3731, #3743). The only risk is a typo or wrong PR link, and the entries here correctly match the referenced PRs (#3757, #3748).

Other factors

The lone human comment (masih) raised a concern about branch targeting but self-resolved it, correctly noting this is changelog-only and lands on main first per the release runbook, consistent with the PR description. No outstanding concerns remain.

[seidroid]

Successfully created backport PR for release/v6.6:

• Backport release/v6.6: Update v6.6 changelog in prep to cut rc4 #3782

[seidroid]

Docs-only PR adding v6.6 changelog entries in prep to cut rc4; the only diff is CHANGELOG.md and there are no code changes to assess. Nothing of note.

Findings: 0 blocking | 2 non-blocking | 0 posted inline

Blockers

• None at the file/PR level.

Non-blocking

• The Cursor second-opinion review file (cursor-review.md) is empty — that pass produced no output. Codex reported no material issues.
• Minor consistency note (non-blocking): this PR also normalizes the casing of an existing entry (RC2 → rc2 for #3731), which is fine and matches the lowercase rc convention used elsewhere in the changelog.

[claude]

LGTM — docs-only changelog update.

Reviewed the diff against the referenced PR numbers (#3781, #3766, #3757, #3748, #3746) and the rc2 casing normalization; entries are accurately described and match the existing changelog format/ordering convention.

Extended reasoning...

Overview

Single-file change to CHANGELOG.md adding five new entries under the v6.6 section (PRs #3781, #3766, #3757, #3748, #3746) and normalizing casing on an existing entry ("RC2" → "rc2"). No code, config, or schema changes. This is a routine changelog update ahead of cutting the v6.6.0-rc4 release, following the same pattern as prior rc changelog PRs (#3746, #3731) already in the file's history.

Security risks

None. The change only adds/edits markdown text in a changelog file; it has no runtime, consensus, or state-machine impact.

Level of scrutiny

Low. This is a mechanical, docs-only PR with no ambiguity — the new lines are well-formed links to existing merged PRs and match the established bullet format exactly. The bug hunting system found no issues, and manual inspection of the diff confirms all referenced PR numbers/descriptions are accurate and consistent with the surrounding entries.

Other factors

The one timeline comment raising a concern (opening against main vs. the release branch) was self-resolved by its author once they realized this is changelog-only and lands on main first per the release runbook, consistent with the PR description. No outstanding unaddressed comments remain.