feat!: rename Items to Values

[millerjp]

feat!: rename Items to Values

Summary

The current Items() method on SyncMap[K, V] returns a slice of values, not key-value pairs. Go convention uses "Values" for this operation (maps.Values, stdlib 1.23). Rename to Values() for consistency before the v1.0.0 API is locked. The module path under github.com/axonops/syncmap is pre-v1.0 and a pkg.go.dev search for importers of the new path returns none, so this is a free rename with no compatibility shim required.

Requirements

1. Rename the method on SyncMap[K, V] from Items → Values in syncmap.go. Signature and body are otherwise unchanged.
2. Rewrite the method's godoc comment so it starts with // Values … and describes the return slice as a point-in-time snapshot with O(n) cost (matching the style established by docs: add doc.go and rewrite godoc on every exported symbol #11; if docs: add doc.go and rewrite godoc on every exported symbol #11 has not merged, apply the style here).
3. Update every Items reference in the test suite to Values:
   • syncmap_test.go (from test: rewrite unit tests to external package with testify/goleak; coverage ≥95% #10): rename the TestItems function to TestValues and each of its subtests (empty_is_empty → empty_is_empty, matches → matches, length_equals_len → length_equals_len — names are the same, just attached to the renamed parent).
   • example_test.go: rename ExampleSyncMap_Items to ExampleSyncMap_Values (if example_test.go exists by merge time — feat!: rename Items to Values #12 adds it; this issue updates it if present).
   • syncmap_bench_test.go: rename BenchmarkItems to BenchmarkValues (if present from feat!: rename Items to Values #12).
   • tests/bdd/features/syncmap.feature: rename the Scenario Values slice matches stored entries (or equivalent — scenario names may already use "Values" if written post-rename).
   • tests/bdd/steps/syncmap_steps.go: rename any step function wired to Items.
4. No other files change. No signature change. No other renames.
5. Commit message subject uses feat!: prefix and the body explicitly names the old and new symbol.
6. Add CHANGELOG.md entry under "Breaking" (CHANGELOG ships in feat: add top-level CompareAndSwap and CompareAndDelete functions #14 — this PR amends the v1.0.0 entry whether feat: add top-level CompareAndSwap and CompareAndDelete functions #14 has merged or not).
7. Add godoc block deprecation note: none — the method is renamed outright, not deprecated.

Acceptance Criteria

1. grep -nE '\\bfunc.*Items\\b' syncmap.go returns no matches.
2. grep -nE '\\bfunc.*Values\\b' syncmap.go returns exactly one match, against the SyncMap[K, V] receiver.
3. git grep -nE '\\bItems\\b' -- syncmap.go syncmap_test.go example_test.go syncmap_bench_test.go tests/bdd/ returns zero matches. (Scope: all production and test files that could carry the old name. String-literal test data for this rename does not exist, so no escape hatch is required.)
4. go doc github.com/axonops/syncmap Values prints a non-empty doc block that begins with Values and contains the substring O(n).
5. go doc github.com/axonops/syncmap Items prints nothing (symbol absent).
6. CHANGELOG.md contains a ## [1.0.0] section with a ### Changed (or ### Breaking) subsection that names Items → Values as a rename.
7. Commit subject matches the regex ^feat!: .
8. make check passes end-to-end; coverage is unchanged or improved by the test rename.
9. CI on the PR green.

Testing Requirements

• make check — green.
• go test -race -run 'TestValues' -count=1 ./... — runs the renamed test and passes. Zero matches when run with -run 'TestItems'.
• go doc inspection per AC chore: add .gitignore, Makefile, and .golangci.yml (#3) #4 / ci: add GitHub Actions CI workflow #5 — output pasted in the PR description.
• pkg.go.dev search for importers of github.com/axonops/syncmap at PR-open time — zero importers confirmed, screenshot or link in the PR description.
• CI green.

Documentation Requirements

• Godoc on Values per Req chore: rename module to axonops/syncmap and bump Go to 1.26 (#1) #2.
• CHANGELOG entry per Req ci: add GitHub Actions CI workflow (#5) #6.
• README API reference table is updated to show Values (README lands in feat: add top-level CompareAndSwap and CompareAndDelete functions #14; if feat: add top-level CompareAndSwap and CompareAndDelete functions #14 has merged, this PR amends the table).

Out of Scope

• README rewrite (owned by feat: add top-level CompareAndSwap and CompareAndDelete functions #14).
• Benchmark / example / BDD file creation (owned by feat!: rename Items to Values #12, feat: add Swap and Clear methods #13) — this PR only updates entries that already exist.
• Any API change other than the rename.
• Deprecation shim — pre-v1.0, no consumers, no shim.

Dependencies

• Blocked by: test: rewrite unit tests to external package with testify/goleak; coverage ≥95% #10 (test file must exist to receive the test rename).
• Soft overlap with docs: add doc.go and rewrite godoc on every exported symbol #11 (godoc style) — either order works; whichever merges second inherits the style of the first.
• Blocks: v1.0.0 (API lock).

Labels

• enhancement
• breaking-change
• P1