fix: replace same-named files in place when uploading to the asset library

[stevenle]

Summary

Dropping (or uploading) files into an asset library folder that already contained files with the same names created a second entry per file with a duplicate name, instead of updating the existing asset.

The cause: AssetBrowser.uploadFiles() always called createAssetFile(), which mints a fresh random asset id, and never checked whether the destination folder already had a file with that name.

Changes

• ui/utils/assets.ts: add findAssetFile(parent, name), an equality query on parent + name (filtered to type: 'file'), with the same parent-path normalization as listAssets().
• ui/components/AssetBrowser/AssetBrowser.tsx: before creating an asset, look up an existing file by destination folder and filename. If one exists, replace its file in place via replaceAssetFile() and fan the change out with syncAssetToDocs(), matching the "Replace file" action in the asset details modal. The success notification reports how many existing files were replaced, and doc fan-out failures surface the same "Some docs failed to update" notification the details modal uses.
• Add assets.find.test.ts covering the lookup (folder scoping, case sensitivity, folders excluded, trailing-slash parent normalization).
• Changeset (patch).

Applies to both the Assets page and the asset picker modal, since both use AssetBrowser.

Test plan

• vitest run ui/utils/assets.find.test.ts ui/utils/assets.delete.test.ts passes.
• eslint and prettier --check on changed files pass; tsc --noEmit -p tsconfig.build.json is clean.
• Manual: drop a file with an existing name into a folder; the existing entry updates (new modifiedAt, new file src) and no duplicate appears. Docs that embed the asset pick up the new file.

🤖 Generated with Claude Code

https://claude.ai/code/session_016L52aaKKrhphsmLBEupcti

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