Add GIF support

[clins1994]

Fixes #90

Summary

• advertise GIF support to Matrix/Beeper capabilities
• send outbound Matrix/Beeper GIFs to LINE as image messages with GIF media metadata
• receive LINE animated images as Matrix fi.mau.gif video messages and fetch original OBS media when needed
• keep plain media uploads compatible with LINE OBS metadata without separately uploading thumbnails

Validation

• CGO_ENABLED=0 go test ./pkg ./pkg/connector ./pkg/connector/handlers ./pkg/e2ee ./pkg/line ./pkg/line/password ./pkg/line/secret
• docker compose build
• docker compose up --build -d and live bridge startup/log smoke check

See comments below for a QA list

Screenshots

Notes

Full local go test $(go list ./... | grep -v /ltsm) and go vet require libolm headers on the host; Docker build validates with olm-dev installed in the builder image.

[clins1994]

QA matrix for GIF support

Current test status

Tested	Case	Status	Notes
✅	Group plain media path	Passed	GIF, JPG/PNG, video, text, and read receipts tested in a group that used the plain LINE media route. Logs showed Server indicates plain media flow for this chat, Sending plain text message (no E2EE), and Uploaded plain media after sending.
✅	1:1 LSON/E2EE path	Passed	GIF, JPG/PNG, video tested both directions. Logs showed encrypted OBS media flow, preview uploads, and successful E2EE video decrypt.
✅	All-E2EE-capable group functional pass	Passed with caveat	GIF/image/video worked functionally in the group. Logs showed group key activity, but Beeper-originated media in that group still logged Sending plain text message (no E2EE), so full LINE E2EE group media coverage is not confirmed.
✅	PNG regression	Passed	PNGs tested successfully.
✅	Basic text/read receipts	Passed	Basic text and read receipts tested successfully.
	Large/weird aspect ratios	Skipped	Explicitly skipped for this QA pass.
	Captions	Skipped	Explicitly skipped for this QA pass.

Core axes

• Direction: Beeper -> LINE, LINE -> Beeper
• Media: GIF, image, video
• Encryption: LSOFF/plain, LSON/E2EE
• Chat type: DM, group
• Source format for Beeper GIF: pasted GIF/image, Beeper fi.mau.gif video, uploaded file if possible

GIF QA

Tested	Case	Chat	Account/Peer	Action	Expected
	G1	DM	LSOFF/plain	Send GIF from Beeper to LINE	Appears in LINE, opens/animates, no “photo unavailable”
✅	G2	Group	LSOFF/plain fallback	Send GIF from Beeper to LINE group	Appears/animates for LINE members
✅	G3	DM	LSON/E2EE peer	Send GIF from Beeper to LINE	Appears/animates in LINE
✅	G4	Group	LSON/E2EE group	Send GIF from Beeper to LINE group	Appears/animates, no decrypt/media errors. Functional pass; logs did not confirm bridge-originated media used LINE E2EE in group.
✅	G5	DM	Any	Send GIF from LINE to Beeper	Appears in Beeper as animated GIF/video, not static JPG
✅	G6	Group	Any	Send GIF from LINE to Beeper group	Appears animated in Beeper
✅	G7	DM	Any	Send Beeper GIF represented as fi.mau.gif video	Converts/sends to LINE successfully
	G8	DM	Any	Send actual image/gif from Beeper	Sends to LINE successfully

Image regression

Tested	Case	Chat	Account/Peer	Action	Expected
	I1	DM	LSOFF/plain	Send JPG/PNG from Beeper to LINE	Appears and opens in LINE
✅	I2	Group	LSOFF/plain fallback	Send JPG/PNG from Beeper to LINE group	Appears and opens
✅	I3	DM	LSON/E2EE peer	Send JPG/PNG from Beeper to LINE	Appears and opens
✅	I4	Group	LSON/E2EE group	Send JPG/PNG from Beeper to LINE group	Appears and opens. Functional pass; logs did not confirm bridge-originated media used LINE E2EE in group.
✅	I5	DM	Any	Send image from LINE to Beeper	Appears in Beeper as image
✅	I6	Group	Any	Send image from LINE to Beeper group	Appears in Beeper as image

Video regression

Tested	Case	Chat	Account/Peer	Action	Expected
	V1	DM	LSOFF/plain	Send MP4/WebM from Beeper to LINE	Appears and plays in LINE
✅	V2	Group	LSOFF/plain fallback	Send video from Beeper to LINE group	Appears and plays
✅	V3	DM	LSON/E2EE peer	Send video from Beeper to LINE	Appears and plays
✅	V4	Group	LSON/E2EE group	Send video from Beeper to LINE group	Appears and plays. Functional pass; logs did not confirm bridge-originated media used LINE E2EE in group.
✅	V5	DM	Any	Send video from LINE to Beeper	Appears and plays in Beeper
✅	V6	Group	Any	Send video from LINE to Beeper group	Appears and plays

Logs to check after each send

docker compose logs --tail=300 matrix-line

Bad signs to look for:

Failed to upload plain media
Failed to upload plain media thumbnail
OBS upload failed
failed to upload GIF
failed to convert video to GIF
failed to download animated image
failed to decrypt
failed to encrypt
send status FAILED

Good signs to look for:

Uploaded plain media after sending
Converted video to GIF for LINE
Successfully sent media/message
status SUCCESS

Minimum smoke set before merge

Tested	Priority	Case
	P0	GIF Beeper -> LINE, LSOFF/plain DM
✅	P0	GIF Beeper -> LINE, LSON/E2EE DM
✅	P0	GIF LINE -> Beeper DM
	P1	JPG/PNG Beeper -> LINE, LSOFF/plain DM
✅	P1	JPG/PNG LINE -> Beeper DM
	P1	MP4 Beeper -> LINE, LSOFF/plain DM
✅	P1	MP4 LINE -> Beeper DM
✅	P2	Repeat GIF/image/video in group chat

Current risk note: the most important regression checks are plain image and plain video Beeper -> LINE, because this PR changes shared plain OBS upload behavior. Those paths were covered in group chat, but not in a plain 1:1 DM.

[clins1994]

QA findings and fixes

While testing the GIF/media support changes, we uncovered and fixed a few issues:

Area	Finding	Fix
GIF rendering in Beeper	GIFs received from LINE could animate but render cropped/cramped inline until opened.	Preserve Matrix image metadata for animated GIFs: mimetype, size, fi.mau.gif, fi.mau.is_animated, width, and height.
GIFs pasted/sent from LINE	GIFs pasted into LINE still cropped because LINE put dimensions in MEDIA_CONTENT_INFO, while the bridge only read MEDIA_THUMB_INFO.	Read width/height from MEDIA_CONTENT_INFO as well as MEDIA_THUMB_INFO.
Multi-account OBS upload	Yuzu sending media failed with an OBS 401 because the encrypted OBS token cache was global and could reuse Caio's token.	Key the OBS encrypted-access-token cache by LINE access token, so each account uses its own OBS token.
Static image rendering	Static images could show cropped inline in Beeper even though opening them showed the full image.	Always include Matrix image info metadata with mimetype, size, width, and height, not only for GIFs.
Video rendering	Videos delivered and played, but Beeper inline previews could crop on receiver views.	Copy LINE MEDIA_THUMB_INFO dimensions into Matrix video info.w / info.h.

Validation performed:

• Group plain LINE media route: GIF, JPG/PNG, video, text, and read receipts passed.
• 1:1 LSON/E2EE route: GIF, JPG/PNG, and video passed both directions.
• PNG regression passed.
• All-E2EE-capable group passed functionally, but logs still showed Beeper-originated group media using the plain LINE route, so that specific full-E2EE group media path is not confirmed.
• Large/weird aspect ratio media and captions were intentionally skipped for this pass.

Relevant commits added during QA:

• 6e0b6ad Fix bridged GIF rendering
• 0294c7e Fix OBS token cache per account
• d757caa Fix Matrix media dimensions

[highesttt]

you switched it from application/octet-stream to application/x-www-form-urlencoded. The other two OBS upload paths in client.go still use octet-stream, and there's a comment on one saying "OBS expects application/octet-stream for binary uploads." Was this intentional / required for GIFs to upload? If it's needed only for GIFs, can we keep octet-stream for the non-GIF callers?

You also removed thumbnails? Did you confirm thumbnails still render on mobile LINE for plain-account image and video sends?

[clins1994]

Found a small bug while testing: GIFs sent via Beeper aren't autoplaying on LINE's end despite the settings being on for auto playing GIFs. This said ... User can still play the GIF on LINE by clicking it and the GIF is recognized as "GIF" on the UI

Here are the settings

It may be present on the main branch but not confirmed