fix(viewer): display caption for album posts with grouped messages

[vadimvolk]

Summary

• Album posts (messages sharing the same grouped_id) lose their caption in the viewer when the message carrying the text is not the first one in reverse-chronological sort order
• Add getAlbumCaption() helper that scans all messages in an album group to find and display the one with non-empty text

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 causes existing functionality to change)
• Documentation update
• Infrastructure/CI change

Database Changes

• Schema changes (Alembic migration required)
• Data migration script added in scripts/
• No database changes

Data Consistency Checklist

N/A — no database code modified.

Root Cause

Messages are sorted newest-first via flex-col-reverse. For an album with grouped_id = 14178103535648053:

id	date	text	role
1261	2026-02-28 07:15:42	(empty)	displayed as "first in album"
1260	2026-02-28 07:15:41	(has caption)	hidden by isHiddenAlbumMessage()

isFirstInAlbum() picks id=1261 (newer, no caption) as the representative message. The template renders msg.text of that message — which is empty. The actual caption on id=1260 is never shown because that message is hidden.

Additionally, without getAlbumCaption in the Vue return object, the template throws TypeError: getAlbumCaption is not a function, crashing the entire Vue app and showing a blank blue page.

Fix

Three changes in src/web/templates/index.html:

1. New getAlbumCaption(msg) helper — scans all messages with the same grouped_id and returns the first non-empty text
2. Template update — changed linkifyText(msg.text) to linkifyText(getAlbumCaption(msg) || msg.text) so albums show the caption regardless of sort order
3. Vue return object — exposed getAlbumCaption so the template can call it

Steps to Reproduce

1. Have an album post (2+ photos, same grouped_id) where the caption is on a message that is not the newest in the group
2. Open the viewer and navigate to that post
3. Before fix: caption is absent; if the album is the first content loaded, the Vue app crashes with TypeError: getAlbumCaption is not a function (blank blue page)
4. After fix: caption displays correctly below the album grid

SQL to verify data is present

SELECT id, date, length(text) as text_len, text, raw_data
FROM messages
WHERE id IN (1260, 1261);

SELECT id, message_id, type, file_name
FROM media
WHERE message_id IN (1260, 1261);

Testing

• Tests pass locally (python -m pytest tests/ -v) — 253 passed, 0 failed (Python 3.14.3)
• Linting passes (ruff check .)
• Formatting passes (ruff format --check .)
• Manually tested in development environment

Security Checklist

• No secrets or credentials committed
• User input properly validated/sanitized
• Authentication/authorization properly checked

Deployment Notes

• Viewer Docker image rebuild needed
• No migration or config changes required

[GeiserX]

Clean fix, correct use of existing album helpers. LGTM.

[GeiserX]

Thanks @vadimvolk! Released as v7.3.2 and deployed.