chore(deps): adopt kaleido 1.4 for docs and tutorials

[Blizzeq]

What does this PR do?

Lifts the kaleido pin in docs/ and examples/ from the deprecated 0.2.x line to >=1.4, and refreshes uv.lock.

Closes #938

The issue's acceptance criteria offered two routes: fix the plotter, or "confirm kaleido >1.3.x fixed the regression upstream". The second one is now met.

@egordm's analysis pinned the bug to _orjson_default in kaleido/_kaleido_tab/_tab.py, which only handled .tolist() and raised on pd.Timestamp, and noted that no upstream PR existed yet. One does now: plotly/Kaleido#461 by @gaoflow adds an isoformat() fallback for datetime-like objects, shipped in kaleido v1.4.0 on 2026-08-31. The fix itself is theirs; what this PR adds is the verification and the lift.

Because it sits in the central serializer rather than at a call site, it covers the paths the plotter-side workaround could not reach, which is why #942 reverted _normalize_x_data and constrained the dependency instead.

Verification

1. The call sites, 1.3.0 versus 1.4.0. Same script, same plotly 7.1.0 and pandas 3.0.5, only kaleido differs:

Figure content	kaleido 1.3.0	kaleido 1.4.0
quantile-fill band (the repro in #938)	TypeError: Type is not JSON serializable: Timestamp	exports
add_vrect with Timestamp bounds	same TypeError	exports
layout.xaxis.range with Timestamps	same TypeError	exports
annotation anchored at a Timestamp	same TypeError	exports

The last three are the call sites #938 lists as not covered by the workaround.

2. The real plotter. ForecastTimeSeriesPlotter with measurements, a forecast and P10/P50/P90 bands, exported through pio.to_image, succeeds on 1.4.0 (60054 bytes). It also succeeds on 1.3.0, because _add_single_quantile_polygon already keeps x as a DatetimeIndex. That workaround is left untouched: it costs nothing and keeps the export robust against future regressions, as the issue describes.

3. The docs build. docs-check run on my fork against this branch: uv sync --frozen then poe docs, green on ubuntu-latest, 24.7 MB of HTML uploaded. nb_execution_mode is cache and a fresh runner has no cache, so the tutorials were executed and their figures exported through kaleido 1.4.0 rather than replayed.

Why >=1.4 and not >=1.0

1.0 through 1.3 still carry the Timestamp bug, so the floor has to be the release containing plotly/Kaleido#461.

This also resolves the other two reasons the pin mentioned: v1 is the maintained line, so the deprecated v0 goes away, and 1.4.0 ships a single py3-none-any wheel, so the missing macOS arm64 wheel that ruled out 0.2.1.post1 is no longer a factor. Note that v1 does not bundle a browser and uses a system Chrome or Chromium, which the CI runner already has, as the green docs build shows.

Type of change

• Bug fix
• New feature
• Breaking change (see checklist below)
• Documentation
• Refactor / chore / CI

Breaking changes checklist

• Public API, config schema, or serialized/pickled objects changed in a way that affects existing users

Not applicable: this only moves a docs/tutorial build dependency. No library code changes.

AI disclosure

• No AI assistance was used (beyond grammar/spelling)
• AI assistance was used — tool(s): Claude Opus 5, as a research and drafting aid under my direction
  • I have reviewed, understand, and can explain all AI-generated code in this PR
  • This is disclosed in a commit message (Assisted-by: Claude Opus 5)

Checklist

• poe all --check passes locally
• Tests added/updated for the change
• Documentation updated (docstrings, user guide, examples) if needed
• Commits are signed off per our DCO (git commit -s)
• PR title follows Conventional Commits

On the two unchecked boxes: there is no code change to test, and the upstream behaviour is already covered by test_orjson_encoder.py in plotly/Kaleido#461. I ran the docs build rather than poe all --check, since that is the job this pin affects; happy to run the full check if you would like it on the record.

[egordm]

Nice find! Overall looks great.

Just a note to remove the comments that are no longer necessary since we no longer pin a specific version.

I will run some final checks tomorrow and merge.