[Marcelo (madpsys)]

Description

Improve the Spokane Deep Dive viewing experience on the documentation site.
All six episode links now open their published MP4 in a new tab with
rel="noopener noreferrer", so readers keep the walkthrough page open.

Each embedded player now has a lightweight JPEG poster extracted from its
own video, rather than appearing empty before playback. The original videos,
English caption tracks, playback controls, and preload="none" remain unchanged.
Update the documentation asset inventory and changelog.

Follow-up to #253. No GitHub issue was filed.

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that changes existing behavior)
• Documentation update
• Infrastructure / CI change

Checklist

• I have read CONTRIBUTING.md
• My changes follow the project's coding standards (PEP 8 for Python, ESLint rules for JS/TS)
• I have added or updated tests that cover my changes
• Python tests pass locally (cd hastelib && hatch run test:pytest) and the UI lints clean (cd ui && npm run lint)
• I have updated the relevant documentation (README, docs/, inline comments)
• I have added an entry to CHANGELOG.md if this is a user-facing change

Testing

• python C:\Users\v-marcelod\.copilot\session-state\504d4bdb-edae-4476-bea2-538bdd615b22\files\verify_spokane_videos.py -- passed. Session-local assertions verify all six distinct published MP4 URLs, safe new-tab attributes, valid matching JPEG posters, and unchanged video sources, caption tracks, and player settings against origin/main.
• C:\Users\v-marcelod\.copilot\session-state\504d4bdb-edae-4476-bea2-538bdd615b22\files\docs-preview-venv\Scripts\python.exe -m pre_commit run -- passed: detect-secrets passed; Black, isort, and flake8 skipped because no Python files changed.
• git diff --cached --check -- passed.
• All six extracted posters were visually inspected; the introduction uses a visible title frame instead of a blank transition.
• py -3.11 -m jupyter_book build docs -- failed before building: jupyter_book is not installed. Dependency restoration encountered unavailable packages in the configured feed; the subsequent installation attempt was interrupted. A full documentation build and browser preview have not been verified.

No persistent automated tests were added. Backend tests
(cd hastelib && hatch run test:pytest) and UI lint (cd ui && npm run lint)
were not run because only documentation and JPEG assets changed.

Additional context

• GitHub strips target="_blank" in its Markdown preview; the new-tab behavior applies to the generated documentation site.
• Standalone MP4 playback does not attach external WebVTT captions. The embedded players still provide English captions.
• Posters are 1280 x 720 JPEGs extracted with FFmpeg: the introduction at 3 seconds and the remaining episodes at 10 seconds.
• No application code, MP4 files, caption files, dependencies, or deployment configuration changed.
• Direct pre-landing review: no blocking findings.

[Copilot]

🟢 Approval recommended

No active review issues are reported for the documentation update, though a full build and browser preview remain unverified.

No open issues 🎉

What changed in this PR

Improves the Spokane Deep Dive documentation experience, following #253’s direct video links, while preserving embedded playback and English captions.

Changes:

• Opens all six episode links in new tabs with noopener noreferrer.
• Adds episode-specific JPEG poster references to the embedded players without changing video sources, captions, or playback settings.
• Updates the asset inventory and changelog.

A full documentation build and browser preview remain unverified.

File	Description
docs/​usage/​spokane-deep-dive.md	Adds new-tab episode links and video preview posters.
docs/​README.md	Includes JPEG previews in the documentation asset inventory.
CHANGELOG.md	Records the preview and new-tab link improvements.

_{Review effort: Balanced}

[Meygha Machado (mgmachado)]

LGTM