Disambiguate and migrate the ModelStream 007/008/009 batches (55 files) #25

• Series: ModelStream
• Files: 55
• Estimated time: ~120 minutes
• Labels: good-first-issue, i16-translations

ModelStream_007 (11 files, "mo007-2" → part uX8iSoDR83g #7.2), ModelStream_008 (22 files across two stems → part Fh1e4sKh3Vs — Tom Ringstrom "Reward is Not Necessary"; two parts share the "#8.1" token, the title picks the right one) and ModelStream_009 (22 files → part CEKWhxnH3-E — Aswin Paul "On efficient computation"; again two "#9.1" parts, the title decides). Verify both disambiguations by opening the two candidate videos before moving.

Scope (from the triage doc, Part A):

• Item ModelStream/ModelStream_007
  • 11 files, stem mo007-2_Active Inference ModelStream 007.2 ~ Conor Heins, pymdp → target translations/uX8iSoDR83g.<bcp47>.srt
• Item ModelStream/ModelStream_008
  • 11 files, stem ActInf ModelStream #008.1 ~ Tom Ringstrom ~ Reward is Not Necessary → target translations/Fh1e4sKh3Vs.<bcp47>.srt
  • 11 files, stem mo008-1_ActInf ModelStream 008.1 ~ Tom Ringstrom ~ Reward is Not Necessary → target translations/Fh1e4sKh3Vs.<bcp47>.srt
• Item ModelStream/ModelStream_009
  • 11 files, stem ActInf ModelStream 009.1 ~ Aswin Paul On efficient computation in active inference → target translations/CEKWhxnH3-E.<bcp47>.srt
  • 11 files, stem mo009-1_ActInf ModelStream 009.1 ~ Aswin Paul On efficient computation in active inference → target translations/CEKWhxnH3-E.<bcp47>.srt

Read first: docs/volunteer-transcript-tasks.md —
sections "The 30-minute task (per file)" and "Exact command pattern".

Steps, per file:

1. Verify the guessed video_id in the item's metadata.json + a YouTube spot-check of the part.
2. Confirm the language by opening the .srt (normalize legacy codes per the migration map).
3. Move with the two-step git mv into translations/<video_id>.<bcp47>.srt.
4. Append the original repo-relative path to the destination item's metadata.json previous_paths.
5. One path-scoped commit per item: translations(<series>): migrate <N> legacy files (I16 triage).

Acceptance criteria:

• every listed file moved (or deleted, if byte-identical to an already-migrated target) with previous_paths recorded
• no listed file remains in the item's Translations/ folder; empty Translations/ and translations_tmp/ removed
• spot-checked target files open as valid subtitles and match the verified part/language