## Motivation
When navigating back to a previous conversation that used a different
model than the one currently loading, the UI incorrectly displayed the
other model's loading/download progress bar instead of the conversation
messages. Additionally, attempting to continue that old conversation by
sending a message would create an entirely new chat rather than
continuing the existing one.
## Changes
All changes in `dashboard/src/routes/+page.svelte`:
1. **Added fallthrough reset in the `chatLaunchState` restore
`$effect`**: When switching to a conversation whose model has no active
instance (not running, not downloading, not loading), the effect now
resets `chatLaunchState` to `"idle"` instead of leaving stale state from
a different model.
2. **Added `skipCreate` parameter to `launchModelForChat()`**: When
continuing an existing conversation (has messages),
`createConversation()` is skipped so the old conversation is preserved
rather than replaced with a new empty one.
3. **Reordered view conditional**: Progress views
(downloading/loading/launching) take priority, then conversation
messages (when idle with messages or model ready), then model selector
(idle with no messages). This ensures:
- Old conversations display normally when their model isn't running
- Download progress shows when relaunching a model for any conversation
- Model selector only appears when there are no messages
## Why It Works
- The `$effect` fallthrough prevents `chatLaunchState` from retaining a
stale value (e.g., `"downloading"`) from Model A when the user switches
to a conversation using Model B that has no active state.
- The `skipCreate` flag ensures `launchModelForChat` can be reused for
both new conversations (from model picker) and continuing existing ones
(from chat input) without always creating a new conversation.
- The reordered view logic ensures each state maps to the correct UI:
active launch → progress, existing messages → chat view, nothing → model
selector.
## Test Plan
### Manual Testing
- Load an old conversation while a different model is downloading →
should see conversation messages, not the other model's loading bar
- Send a message from that old conversation → model should
launch/download with progress shown → conversation continues with the
response appended
- Select a new model from the picker → should still create a new
conversation as before
- New conversation with model download → progress bar shows correctly
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Co-authored-by: Claude Opus 4.6 <[email protected]>
