[Quality] Prepare v0.5.2 release surfaces

[luoyuctl]

Scope

Closes #245.

• Bump the engine/report version constant to 0.5.2.
• Align README, README.zh-CN, Homebrew formula, site metadata, and static demo report version surfaces with v0.5.2.
• Add concise v0.5.2 release candidate notes for the merged Fix Claude JSONL parallel tool turn metrics #243 Claude Code JSONL parallel tool metrics fix.

Non-goals

• No parser or runtime behavior changes beyond the version constant.
• No npm wrapper/package restoration.
• No Homebrew publish action, tag creation, GitHub Release creation, or external posting.
• No hosted tracing, uploaded-log, security-enforcement, or new parser/source support claims.

Validation

• git diff --check
• go test ./...
• go build -o /tmp/agenttrace-245-check ./cmd/agenttrace
• /tmp/agenttrace-245-check --version
• scripts/ci/check-release-surfaces.sh
• AGENTTRACE_BIN=/tmp/agenttrace-245-check AGENTTRACE_CI_OUT=/tmp/agenttrace-245-ci scripts/ci/check-docs-commands.sh
• scripts/ci/check-pages-artifact.sh site
• AGENTTRACE_BIN=/tmp/agenttrace-245-check AGENTTRACE_CI_OUT=/tmp/agenttrace-245-ci scripts/ci/check-output-contract.sh
• AGENTTRACE_BIN=/tmp/agenttrace-245-check AGENTTRACE_CI_OUT=/tmp/agenttrace-245-ci scripts/ci/check-deterministic-output.sh
• AGENTTRACE_BIN=/tmp/agenttrace-245-check AGENTTRACE_CI_OUT=/tmp/agenttrace-245-ci scripts/ci/check-report-semantics.sh

[luoyuctl]

Quality Gatekeeper Review

Verdict: PASS
Risk: Medium
Lane: quality / growth
Checks:

• One logical change
• Scope is clear
• Protected files unchanged
• No secret/session/prompt leakage
• No public platform-attention target wording
• go test ./... passed
• go build -o /tmp/agenttrace-review-pr-246 ./cmd/agenttrace passed
• --doctor and demo JSON/HTML overview passed
• Docs/tests updated if needed

Notes: PR updates only the v0.5.2 release surfaces requested by #245: engine version, README/Homebrew/site/demo-report version metadata, and concise CHANGELOG release candidate notes for the already-merged #243 fix. GitHub mergeStateStatus is CLEAN; CI Test and build is SUCCESS; changed files are limited to CHANGELOG.md, README.md, README.zh-CN.md, homebrew/Formula/agenttrace.rb, internal/engine/engine.go, site/demo-report.html, and site/index.html.

Additional release-surface checks run from temporary worktree ../agenttrace-review-pr-246:

• git diff --check origin/master HEAD
• /tmp/agenttrace-review-pr-246 --version -> agenttrace v0.5.2
• scripts/ci/check-release-surfaces.sh
• scripts/ci/check-output-contract.sh
• scripts/ci/check-deterministic-output.sh
• scripts/ci/check-report-semantics.sh
• scripts/ci/check-docs-commands.sh
• scripts/ci/check-pages-artifact.sh site

Decision: PASS and eligible for automatic squash merge. Handoff to: Growth after merge, re-run #244 Release Gate on the merged commit before creating tag/release; this PR does not authorize npm/Homebrew publication or external posting.