create_update_video_ad

Create OR update a VIDEO ad on Facebook, Instagram, LinkedIn, and/or Reddit.
                                TO UPDATE: include `id`; to CREATE: omit it.

                                CREATIVE WORKFLOW:
                                  1. Upload the video via `upload_video_creative` → response gives `id` (the videoLibraryId).
                                  2. Pass that integer as `creativeID` here.
                                  - For Reddit, ALSO upload a still thumbnail via `upload_image_creative` and pass
                                    its imageLibraryId as `redditThumbnailLibraryId` (required; the video cannot
                                    be its own thumbnail).

                                ALSO KNOWN AS: create video ad, update video ad, edit video ad,
                                modify video ad, video creative, post video, video post, motion ad.

                                KEYWORDS: video, create, update, edit, modify, ad, ads, video ad, video ads, mp4, motion,
                                video creative, video campaign, video upload, video post, video promo,
                                LinkedIn video, Facebook video, Instagram video, Reddit video, IG reel.

                                CLIENT-SIDE VALIDATION (refuses what the platform UI would also reject):
                                  - adName: required, max 50 chars, pattern `[a-zA-Z0-9 _.?,:'/+\-=&;%$#\[\]|()]`.
                                  - creativeID: required integer (videoLibraryId from `upload_video_creative`).
                                  - Landing-page URL is per channel (`facebookDisplayURL`,
                                    `instagramDisplayURL`, `linkedinDisplayURL`, `redditDisplayURL`).
                                    Required for FB/IG/LinkedIn, optional for Reddit. Per-channel
                                    caps: LinkedIn max 2000, Reddit max 100, FB/IG no length rule.
                                    For VIDEO the URL MUST be ABSOLUTE (http:// or https:// is
                                    required); inputs like `metadata.io` or `www.foo.com` are
                                    rejected the same way the UI rejects them. If only one channel's
                                    URL is set the server fans it across the other targeted channels.
                                  - LinkedIn: linkedinText (max 3000, OPTIONAL for VIDEO unlike IMAGE),
                                    linkedinHeadline (required, max 200), linkedinCTA (required, valid enum).
                                    linkedinDescription is NOT accepted on VIDEO ads (the platform DTO
                                    does not declare it).
                                  - Facebook: metaCTA (required), facebookText (required, no length rule on
                                    Facebook), facebookHeadline (required, max 250), facebookDescription
                                    (optional, max 300).
                                  - Instagram: metaCTA (required), instagramText (required, max 125),
                                    instagramHeadline (required, max 40), instagramDescription (optional, max 30).
                                  - FB+IG ad with one body text: set just one of facebookText / instagramText
                                    and the server copies it across (capped at the receiving channel's limit).
                                    Set both explicitly only when you want per-channel copy.
                                  - Reddit: redditHeadline (required, max 300), redditCTA (required, valid enum),
                                    redditThumbnailLibraryId (REQUIRED — separate IMAGE library id).

                                COMMON CTA VALUES: same as `create_update_image_ad` (see that tool for the lists).

                                See `create_update_image_ad` for image/GIF ads (the URL rule is looser there).