fix(inspect): video metadata carrier parity between Images and Inspect (#275)

* fix(video): select one prompt carrier from per-key or comment tags

Current ComfyUI savers write one container tag per key (prompt, workflow,
parameters, comfyassets_prompt_pairs); only the old VideoHelperSuite comment
envelope was read. select_video_carrier picks exactly one carrier in the
order per-key tags, comment envelope, description: the first with a role
key wins, else the first with a workflow, and carriers never merge.
Matroska upper-cased tag names fold on our side; differing fold-duplicates
fail the read like duplicate PNG keys, identical ones are one record.
Per-key values stay original-text; envelope objects are reserialized.

* fix(inspect): read per-key video prompt tags

The inspector asked ffprobe only for comment and description, so videos
written by core SaveVideo/SaveWEBM and current VideoHelperSuite (one tag per
key) were inspected as having no metadata. It now asks for
prompt,workflow,parameters,comfyassets_prompt_pairs,comment,description and
hands the tags to the shared carrier selector. ffprobe stdout is bounded at
the role and workflow budgets plus 64 KiB of envelope; past that it probes
once more without the workflow tag within the role budget and marks the
per-key workflow limited, while an over-budget envelope still fails the
read. Differing fold-duplicate tags fail like duplicate PNG keys.

* fix(video): scan videos written by current ComfyUI savers

The output scan and live monitor read container tags through
metadata_from_tags, which now delegates to the shared carrier selector, so
per-key prompt, workflow, parameters and comfyassets_prompt_pairs tags
(including Matroska upper-cased names) are ingested with the default
resolver profile exactly like the same graph in a PNG. Fold-duplicate tags
and null markers are skipped quietly. Pins the behavior with a mocked
ffprobe scan test and real MP4/MKV/WebM round trips when ffmpeg is present.

* docs(testing): document video carrier selection

Record the shared video carrier order (per-key tags, comment envelope,
description), the fold-duplicate rule, the 6 MiB + 64 KiB probe bound with
the role-only re-probe and limited workflow, and that scans read the same
carrier as the inspector.

* fix(inspect): size video probe bounds for JSON escaping, exact-case envelopes

ffprobe JSON-escapes tag text, so bounds measured on its stdout could mark a
video workflow limited, or fail a role record, that the identical PNG reads
within its decoded budget. The first probe now allows twice the role and
workflow budgets plus 64 KiB (12 MiB + 64 KiB) and the role-only re-probe
twice the role budget plus 64 KiB, leaving the decoded per-record budgets as
the only gate; a reader-level test reads near-budget quote-dense records as
PNG and as video and asserts identical metadata and formats.

Envelope keys (comment, description) are matched exactly as the legacy
readers did; only the four per-key carriers fold Matroska case. Fixtures can
write the legacy ilst comment atom (metadata_tags=False), and the docs now
say the admin scan reads the carrier while the live monitor still processes
images only, with a follow-up recorded in TESTING.md.

docs/prompt-inspector.md

@@ -29,6 +29,12 @@ Each role has `status` (`resolved`, `absent`, `unresolved`, or `ambiguous`), `te
 (string only when resolved, otherwise null), and `source`. Inspection does not
 index files, alter saved prompts, run scans, or decode image pixels. PNG text and
 video probe output are bounded; unsupported or malformed evidence remains
-unresolved rather than becoming sendable placeholder text.
+unresolved rather than becoming sendable placeholder text. Videos are read from
+one container carrier: the per-key tags written by core SaveVideo/SaveWEBM and
+current VideoHelperSuite (`prompt`, `workflow`, `parameters`,
+`comfyassets_prompt_pairs`), else the old VideoHelperSuite `comment` envelope,
+else `description`. The admin scan reads the same carrier, so Images and
+ingestion agree on a video's prompts (see TESTING.md for the order and budgets;
+the live monitor processes images only).
 
 Python route changes require restarting ComfyUI. Browser assets require a refresh.