Render timestamps as local-with-offset for humans, UTC for JSON

[daniel-thom]

Summary

• Apply a single timestamp display policy across CLI, TUI, dash, and Python client:
  • Humans (TUI, dash, CLI table mode, CLI detail printouts) see local time with an explicit ±HHMM offset suffix (e.g. 2026-05-25 14:30:00 -0700)
  • JSON mode keeps the server's raw UTC RFC3339 value
• Server stores UTC already, so this is purely a client-side rendering change. File mtimes get the same treatment as RFC3339 timestamps.
• Includes the new job.start_time field from PR Add start_time and compute_node_id to the job table #350 — it lands consistently from day one rather than inheriting the prior raw-passthrough pattern.

Why

Timestamp display had drifted into three different conventions: raw RFC3339 in some CLI sites, local-without-offset in others, and silent local in the dash. A user SSH'd into a remote host couldn't tell whether a dash time was local or server-side. Now every human surface shows a self-describing string.

What changed

• src/client/utils.rs — added format_local_timestamp(&str) and format_local_timestamp_epoch(f64) helpers, plus a shared HUMAN_TIMESTAMP_FORMAT constant and three unit tests.
• CLI (workflows.rs, results.rs, compute_nodes.rs, jobs.rs) — route detail-view printlns and tabled table rows through the helper. JSON paths untouched (already UTC RFC3339).
• CLI events.rs — format_timestamp_ms (human) now includes the offset; new format_timestamp_ms_utc formats the JSON convenience timestamp_formatted field as UTC RFC3339 with millisecond precision.
• TUI (ui.rs, components.rs) — format_timestamp (file mtimes, was UTC Z) and format_timestamp_ms (events, was local-no-offset) both now emit local-with-offset; job-detail popup formats start_time through the new helper.
• Dash (app-utils.js, app-job-details.js) — formatDateLocal appends ±HHMM; app-job-details.js routes job.start_time through formatTimestamp instead of raw escapeHtml.
• Python (common.py) — convert_timestamp now returns a tz-aware UTC datetime (datetime.fromtimestamp(ts/1000, tz=timezone.utc)) so callers can .astimezone() for local rather than silently inheriting the client zone. Docstring updated.

Notes

• CSV output reuses the same tabled struct as table mode, so CSV is also local-with-offset. If a downstream tool wants machine-readable UTC, that would need a separate row struct — happy to follow up if needed.
• The format_timestamp_ms in events keeps millisecond precision (events arrive frequently enough that subsecond ordering matters); the file-mtime / RFC3339 helpers use second precision.

Test plan

• cargo build --workspace — clean
• cargo fmt -- --check — clean
• cargo clippy --all --all-targets --all-features -- -D warnings — clean
• dprint check — clean
• cargo nextest run --lib — 372/372 pass (3 new tests for the helpers)
• Manual: launch TUI, eyeball file mtime and event timestamps for offset suffix
• Manual: open dash, eyeball workflow/event/file timestamps for offset suffix; verify job detail "Start Time" renders as local-with-offset
• Manual: torc results list <wf> and torc -f json results list <wf> — confirm table shows local, JSON shows UTC RFC3339
• Manual: Python from torc.common import convert_timestamp; print(convert_timestamp(...).tzinfo) returns UTC

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Unifies timestamp rendering across Torc’s human-facing clients (CLI/TUI/dash/Python) so humans consistently see local time with an explicit ±HHMM offset, while JSON output preserves UTC RFC3339 values.

Changes:

• Added shared Rust timestamp helpers (format_local_timestamp*) and updated CLI/TUI call sites to use local-with-offset formatting for human output.
• Updated dash timestamp formatting to append the local offset and updated job details to format job.start_time consistently.
• Updated Python convert_timestamp to return a tz-aware UTC datetime to prevent naive/local-time ambiguity.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
torc-dash/static/js/app-utils.js	Adds ±HHMM suffix for local timestamp rendering in the dash.
torc-dash/static/js/app-job-details.js	Routes job.start_time through the dash timestamp formatter.
src/tui/ui.rs	Updates TUI timestamp formatting (events + file mtimes) to include ±HHMM and adjusts column widths.
src/tui/components.rs	Formats job.start_time in the job details popup via the shared helper.
src/client/utils.rs	Introduces shared human timestamp format constant + RFC3339/epoch formatting helpers and tests.
src/client/commands/workflows.rs	Formats workflow timestamps for human list/detail output via helper (JSON unchanged).
src/client/commands/results.rs	Formats result completion time for human list/detail output via helper.
src/client/commands/jobs.rs	Formats job start time for human detail output via helper.
src/client/commands/events.rs	Human event timestamps now include offset; JSON “formatted” timestamp becomes UTC RFC3339 w/ millis.
src/client/commands/compute_nodes.rs	Formats compute node start time for human list/detail output via helper.
python_client/src/torc/common.py	Makes convert_timestamp return tz-aware UTC datetimes and updates docstring accordingly.

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