release: prepare v0.2.0 — CHANGELOG, chart bump, README link (refs #62)

[Coldwings]

What

Prepares the v0.2.0 release (decision recorded in #62):

1. CHANGELOG.md (new, tracked): full v0.2.0 entry —
   • Additions: the four 2026-08-13 direct commits (EndpointSlice discovery module + internal/node extraction, Helm/Fluid samples, non-range origin passthrough, tracker idle eviction), explicitly marked as direct commits;
   • Fixes: all 30 merged PRs (engine: validate relayed block length against geometry before caching (fixes #1) #23–cluster,node: member-ID alphabet guards the epoch framing; lifecycle/tracker docs (fixes #21) #44, cluster: report invalid roster IDs via OnError; assert the epoch collision (fixes #46) #47, node: closeable admission gate; never close the store under a live handler (fixes #45) #48, engine: reject suffix ranges on empty objects (fixes #49) #56–engine/fetch/chunk: reject peer block indices that overflow signed range geometry (fixes #52) #61) grouped by subsystem — coverage machine-checked, each PR appears exactly once;
   • Upgrade notes: the verified wire-compat statement (Hash64 / HRW score / ChunkKey / epoch framing byte-identical to v0.1.0; cache-identity splits limited to malformed URLs and duplicated static-peer IDs, no correctness impact);
   • Verification: vet/race/cover/CI status at the tagged commit;
   • a v0.1.0 baseline entry.
2. deploy/helm/dart/Chart.yaml: chart version 0.1.0 → 0.2.0, appVersion dev → v0.2.0 (first tag the chart can name).
3. README.md: links CHANGELOG.md from the Documentation section.

The version string itself needs no code change: binaries stamp -ldflags -X main.version=... at build time.

After this merges, I will tag v0.2.0 (annotated) on the merge commit and create the GitHub Release with notes derived from the changelog, then close #62.

Refs #62

Verification

Docs/manifest-only change; still ran the full trio: gofmt clean; go vet ./... clean; go test ./... -race -count=1 13/13 PASS; -cover PASS.

[Coldwings]

@copilot please review. Focus on: factual accuracy of the changelog inventory against the merged PR list (#23-#44, #47, #48, #56-#61), the wire-compat upgrade-note claims, and the Chart.yaml version/appVersion conventions. Do NOT push commits; post review comments only.

[Copilot]

@copilot please review. Focus on: factual accuracy of the changelog inventory against the merged PR list (#23-#44, #47, #48, #56-#61), the wire-compat upgrade-note claims, and the Chart.yaml version/a...

Review finding: Chart.yaml now says appVersion: "v0.2.0", but values.yaml still defaults image.tag: dev, and templates/_helpers.tpl renders the image solely from .Values.image.tag. Thus the chart metadata names v0.2.0 while a default install deploys dart:dev/dart-k8s:dev; either bump the default tag (and its explanatory comment) or retain appVersion: "dev" until release images are available. I also cross-checked the listed PRs: the 30-number inventory and subsystem grouping are complete, and the direct-commit hashes/dates match GitHub. The wire-compat wording is consistent with the documented changes, subject to the stated malformed/duplicate-ID exclusions.

[Coldwings]

@copilot addressed: kept appVersion v0.2.0 as chart metadata and clarified values.yaml — images are source-built (no registry publication), dev is the local-build default, and release deploys should set tag to the chart's appVersion. Please re-review.

[Copilot]

@copilot addressed: kept appVersion v0.2.0 as chart metadata and clarified values.yaml — images are source-built (no registry publication), dev is the local-build default, and release deploys should...

Re-review: the values.yaml clarification resolves the deployment/documentation mismatch—dev is explicitly the source-build default, and release users are told to set image.tag to v0.2.0. One minor stale comment remains in Chart.yaml: appVersion tracks the DART image tag the chart defaults to is no longer true because the chart defaults to image.tag: dev. Please change that comment to say it identifies the release image/tag the chart targets (or equivalent).

[Coldwings]

@copilot fixed the stale Chart.yaml comment — appVersion now documented as naming the targeted release image tag, not the chart default. Please re-review.

[Copilot]

@copilot fixed the stale Chart.yaml comment — appVersion now documented as naming the targeted release image tag, not the chart default. Please re-review.

Re-review complete: the Chart.yaml comment now accurately distinguishes the targeted release image tag (appVersion) from the source-build default (image.tag: dev). The Helm metadata and accompanying values.yaml guidance are consistent; no further changes needed.