fix(tasks): File to… adds the task to the channel feed as a thread item

[adamleithp]

Problem

In the task list, the File to… menu option on a task didn't add the task to the channel as a thread item.

Why: A channel has two sides. The desktop file-system rows back the channel's Artifacts / Recents tabs, while the Slack-style feed (the thread items) is read from getTasks({ channel }). "File to…" only wrote the file-system row, so the task never showed up in the channel feed — only in its file browser.

Changes

• Added useFileTaskToChannelFeed, which resolves the folder channel's backend channel by name (resolve-or-create for public channels, mapping the me folder onto the personal channel) and sets the task's channel, then invalidates the feed query.
• The file-to-channel handler in useTaskContextMenu now files to both sides: the existing folder filing plus the new feed association, so a filed task appears as a thread item in the channel.

How did you test this?

• Added useFileTaskToChannelFeed.test.ts covering public-name resolution, the me → personal-channel mapping, and the resolve-or-create fallback — all passing.
• pnpm --filter @posthog/ui typecheck and Biome check pass on the changed files; the full @posthog/ui unit suite passes.

Automatic notifications

• Publish to changelog?
• Alert Sales and Marketing teams?

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Created with PostHog Code

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[github-actions]

React Doctor found no issues in the changed files. 🎉

_{Reviewed by React Doctor for commit 116289c.}