fix[ios channels]: scroll message list when input focused"

[peterchinman]

on iOS we need to scroll the message list, when the user is near the bottom, when the main input is focused.

[coderabbitai]

📝 Walkthrough

Walkthrough

Introduces an iOS-specific main-input keyboard handler and a shared near-bottom constant. Channel.tsx now exposes the main input element via a Solid signal and wires the new handler to scroll the message list to bottom when the keyboard appears if the list was previously near bottom.

Changes

Cohort / File(s)	Summary
Channel input & handler js/app/packages/channel/Channel/Channel.tsx, js/app/packages/channel/Channel/create-main-input-keyboard-handler.ts	Added channelInputEl signal and updated ChannelInputContainer ref to store the element. Introduced createMainInputKeyboardHandler(...) which listens for touchstart to track "near bottom" state and reacts to keyboardWillShow on iOS to call navigation()?.scrollToBottom(). Listeners are scoped and cleaned up.
Scroll threshold constant js/app/packages/channel/Channel/constants.ts, js/app/packages/channel/Channel/ThreadList.tsx	Extracted local NEAR_BOTTOM_THRESHOLD = 50 into an exported NEAR_BOTTOM_THRESHOLD constant and updated ThreadList.tsx to import and use it.

Possibly related PRs

• fix(new-channels): better thread scrolling + fix data-channel-nav highlight-nav highlight issue #2100 — Modifies Channel.tsx and touches keyboard/scroll behavior; likely overlaps with the new main-input keyboard handling.
• feat(new-channels): improved scrolling stability #2433 — Adjusts channel scrolling logic and introduces/uses the shared near-bottom threshold constant.
• fix(new-channels): scroll jankyness, thread stability improvements #2110 — Refactors ThreadList scroll intent handling and intersects with the relocated NEAR_BOTTOM_THRESHOLD and scroll behavior changes.

🚥 Pre-merge checks | ✅ 2

✅ Passed checks (2 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title follows conventional commits format with 'fix' prefix and clearly describes the main change: scrolling message list when input is focused on iOS channels.
Description check	✅ Passed	The pull request description directly describes the changeset: implementing iOS-specific functionality to scroll the message list when the input is focused.

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[github-actions]

Preview: https://peter-scroll-channel-when-inpu-crolgg.preview.macro.com/app (b73a0e7)

[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against the current code and only fix it if needed.

Inline comments:
In `@js/app/packages/channel/Channel/create-main-input-keyboard-handler.ts`:
- Line 5: NEAR_BOTTOM_THRESHOLD is duplicated; extract it into a single exported
constant in a shared module (e.g., create a exported NEAR_BOTTOM_THRESHOLD in a
common/constants or channel/constants file) and replace the local declaration in
create-main-input-keyboard-handler.ts and the one in ThreadList.tsx with imports
from that shared module so both scroll logic paths use the same constant (update
any references to NEAR_BOTTOM_THRESHOLD accordingly).
- Around line 23-33: The captureNearBottom function uses
document.querySelector('[data-channel-scroll]') which can pick the wrong
container when multiple channels are mounted; update captureNearBottom (in
create-main-input-keyboard-handler / captureNearBottom) to query the scroll
element scoped to the current channel instance (e.g., use a channelRoot or
container element captured by the outer createMainInputKeyboardHandler factory
and call channelRoot.querySelector('[data-channel-scroll]') instead of
document.querySelector), keep the existing logic that computes
distanceFromBottom and sets wasNearBottom using NEAR_BOTTOM_THRESHOLD, and
ensure the outer factory receives/retains the correct channel root element so
the lookup is instance-scoped.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

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Review profile: ASSERTIVE

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Run ID: 348713af-522d-4789-8314-a2dbd107a634

📥 Commits

Reviewing files that changed from the base of the PR and between e0f57d9 and 24a3ead.

📒 Files selected for processing (2)

• js/app/packages/channel/Channel/Channel.tsx
• js/app/packages/channel/Channel/create-main-input-keyboard-handler.ts