Lazy-load yt-dlp media players in card template

[FellowTraveler]

Companion to ArchiveBox/ArchiveBox#1819.

Moves the yt-dlp media player behavior into the yt-dlp plugin card template, where plugin-specific rendering belongs.

The card now:

• renders lightweight play buttons and file links initially
• creates the video/audio element only after the user clicks
• keeps non-browser-playable files as regular links
• URL-encodes generated href and data-src values so filenames with reserved characters still work

Also fixes Claude integration test behavior for public CI:

• live Claude Code / Anthropic tests skip when ANTHROPIC_API_KEY is absent instead of failing the PR
• explicit CLAUDECODE_BINARY env overrides are respected before hydrated binary defaults

Verification:

PYTHONPATH=/Users/au/src/abx-plugins PATH=/Users/au/src/ArchiveBox/.venv/bin:$PATH pytest abx_plugins/plugins/ytdlp/tests/test_ytdlp.py::test_card_template_loads_browser_media_on_click abx_plugins/plugins/ytdlp/tests/test_ytdlp.py::test_card_template_links_non_browser_media_without_player -q
2 passed

ANTHROPIC_API_KEY unset:
PYTHONPATH=/Users/au/src/abx-plugins PATH=/Users/au/src/ArchiveBox/.venv/bin:$PATH pytest abx_plugins/plugins/claudecode/tests/test_claudecode.py abx_plugins/plugins/claudecodeextract/tests/test_claudecodeextract.py abx_plugins/plugins/claudecodecleanup/tests/test_claudecodecleanup.py -q
26 passed, 7 skipped

[cubic-dev-ai]

1 issue found across 2 files

<sub>Reply with feedback, questions, or to request a fix.

Re-trigger cubic</sub>

[FellowTraveler]

CI note: this PR also fixes the Claude plugin failures currently visible on ArchiveBox/ArchiveBox#1819.

Those ArchiveBox checks clone/test upstream ArchiveBox/abx-plugins; on current upstream, the Claude Code integration fixture fails public PR CI when ANTHROPIC_API_KEY is absent. This PR changes that behavior to skip live Claude/Anthropic integration tests when credentials are not present, while keeping non-live tests green.

Local verification with ANTHROPIC_API_KEY unset:

PYTHONPATH=/Users/au/src/abx-plugins PATH=/Users/au/src/ArchiveBox/.venv/bin:$PATH pytest abx_plugins/plugins/claudecode/tests/test_claudecode.py abx_plugins/plugins/claudecodeextract/tests/test_claudecodeextract.py abx_plugins/plugins/claudecodecleanup/tests/test_claudecodecleanup.py -q
26 passed, 7 skipped