Rename image size constants and require them as params

POST_IMG_MAX no longer described post images, so rename it to the
semantically accurate pair: POST_IMG_MAX_SIZE (4000px/2MB, post images
and pasted URLs) and PROFILE_IMAGES_MAX_SIZE (2000px/1MB, avatars,
banners, onboarding, link thumbnails).

Drop the constant defaults from compressImage, compressIfNeeded, and
getResizedDimensions; callers now pass the appropriate max config object
directly so the size policy lives at the call site. Web avatar/banner
edits now use PROFILE_IMAGES_MAX_SIZE, matching the native profile path.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/lib/api/index.ts

@@ -21,6 +21,7 @@ import {sha256} from 'js-sha256'
 import {CID} from 'multiformats/cid'
 import * as Hasher from 'multiformats/hashes/hasher'
 
+import {POST_IMG_MAX_SIZE} from '#/lib/constants'
 import {isNetworkError} from '#/lib/strings/errors'
 import {shortenLinks, stripInvalidMentions} from '#/lib/strings/rich-text-manip'
 import {logger} from '#/logger'
@@ -323,7 +324,10 @@ async function resolveMedia(
     const images: AppBskyEmbedImages.Image[] = await Promise.all(
       imagesDraft.map(async (image, i) => {
         logger.debug(`Compressing image #${i}`)
-        const {path, width, height, mime} = await compressImage(image)
+        const {path, width, height, mime} = await compressImage(
+          image,
+          POST_IMG_MAX_SIZE,
+        )
         logger.debug(`Uploading image #${i}`)
         const res = await uploadBlob(agent, path, mime)
         return {