[NUAAwqy]

Fixes #1669

Root cause

The server-rendered dates ignore the site-configured time zone in three places (verified on dev; see #1669 for the full report and the executed repro):

1. timeFormatISO (internal/base/server/http_funcmap.go) called time.LoadLocation(tz) and discarded the loaded location — the same pattern fix(day): render unix timestamps in the time zone the caller asked for #1659 fixed in day.Format — then formatted in the server's local zone with the layout 2006-01-02T15:04:05.000Z, where the trailing Z is a literal. Every server-rendered <time datetime="..."> (question detail ×4, comment, question list, tag detail) carried the server-local wall clock labeled as UTC.
2. The JSON-LD DateCreated fields (internal/controller/template_controller.go) were built with time.Unix(...) in the server zone, so the schema.org data carried the deployment's zone instead of siteInfo.Interface.TimeZone.
3. The same-year decision in translatorTimeFormat compared calendar years in the server zone, not the display zone: two instants sharing a year in Tokyo sit on opposite sides of New Year in Los Angeles.

Proposed changes

• pkg/day: extract the shared zone resolver Location(tz) (empty/unknown → server local, the semantics fix(day): render unix timestamps in the time zone the caller asked for #1659 established) and add FormatISO(unix, tz) rendering a real ISO-8601 marker (+09:00, or Z only for UTC). Format now uses Location too (behavior unchanged on dev).
• http_funcmap.go: timeFormatISO delegates to day.FormatISO; the dead LoadLocation call is removed; the year-boundary decision moves into sameYearInZone(a, b, tz) and is made in the display zone.
• template_controller.go: the JSON-LD DateCreated values are rendered with .In(day.Location(siteInfo.Interface.TimeZone)).

Verification

All commands run with Go 1.25.14 (linux/amd64) on the dev branch with these changes applied.

• go test ./pkg/day/ -v — TestFormat, TestFormatTimezone (5 subtests), TestFormatUnknownTimezoneFallsBackToLocal (3 subtests), TestLocation, TestFormatISO (5 subtests) — all PASS, ok github.com/apache/answer/pkg/day 0.368s.
• go test ./internal/base/server/ -v — TestTimeFormatISO (4 subtests), TestTimeFormatISOFallsBackToLocalForUnknownZone (3 subtests), TestSameYearInZone — all PASS, ok github.com/apache/answer/internal/base/server 0.040s.
• Before/after for the repro from Server-rendered <time datetime> and JSON-LD dates ignore the site time zone (server-local wall clock labeled as UTC) #1669 (process with TZ=Asia/Shanghai): before timeFormatISO("Asia/Tokyo", 1700000000) = 2023-11-15T06:13:20.000Z, after 2023-11-15T07:13:20.000+09:00.
• go build ./... clean; go test ./internal/... ./pkg/... ./plugin/... ./cmd/... passes everywhere except internal/repo/repo_test and plugin/plugin_test, which panic on pristine dev too (the sandboxed sqlite cannot write: "attempt to write a readonly database") — pre-existing environment limitation, unrelated to this change.

Changelog

• fix(template): render server-side <time datetime> attributes and JSON-LD dates in the site time zone with valid ISO-8601 markers, instead of the server-local wall clock labeled as UTC