feat(scan): probe & store total video/audio duration at scan time

[detain]

Why

The web player's scrubber starts with a tiny total length that grows as the file streams, because duration was only probed lazily at transcode time. Seeking before the playhead reaches a point was unreliable. The user wants the full length known up front.

What

• MediaScanner now probes each time-based file's total duration via the existing FfmpegRunner::probe() as it is indexed and stores it under metadata_json['duration_seconds'] — the field MediaItemShaper already exposes to the API as duration and the player reads.
• Probes only video/movie/episode/audio; never image/book/photo.
• Backfill: on re-scan, already-indexed items missing a positive duration get probed and updated (preserving other metadata).
• Matches TranscodeManager::persistProbedDuration() key/type/(int) round((float)) rounding so the scan- and transcode-time paths agree.
• Probe failures are caught and never abort a scan.
• Wired FfmpegRunner into the MediaScanner autowire definition.

Tests

7 new MediaScannerTest cases (mocked FfmpegRunner): new-video populated, audio probed, image/book never probed, null/throw does not abort, re-scan backfill, no re-probe when present. Full Unit/Media suite green (930 tests).

Verify

phpcs PSR-12 clean · phpstan L9 [OK] · phpunit green.

🤖 Generated with Claude Code

[chatgpt-codex-connector]

You have reached your Codex usage limits for code reviews. You can see your limits in the Codex usage dashboard.

[codacy-production]

Not up to standards ⛔

🔴 Issues 3 medium · 5 minor

Alerts:
⚠ 8 issues (≤ 0 issues of at least minor severity)

Results:
8 new issues

Category	Results
Comprehensibility	4 minor
CodeStyle	1 minor
Complexity	3 medium

View in Codacy

🟢 Metrics 41 complexity · 0 duplication

Metric	Results
Complexity	41
Duplication	0

View in Codacy

_{NEW Get contextual insights on your PRs based on Codacy's metrics, along with PR and Jira context, without leaving GitHub. Enable AI reviewer
TIP This summary will be updated as you push new changes.}

[codecov]

Codecov Report

❌ Patch coverage is 81.48148% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 58.89%. Comparing base (7cb6256) to head (5f1d6e9).
⚠️ Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
src/Media/Library/MediaScanner.php	79.16%	10 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff              @@
##             master     #307      +/-   ##
============================================
+ Coverage     58.87%   58.89%   +0.02%     
- Complexity    12524    12545      +21     
============================================
  Files           474      474              
  Lines         41195    41248      +53     
============================================
+ Hits          24252    24295      +43     
- Misses        16943    16953      +10     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.