Populate hydrograph and monthly flow charts based on "mid" or "extremes" mode

[cstephen]

Xref: ua-snap/data-api#709

This PR works with the aggregate_hydroviz_endpoints branch of the Data API to make the hydrograph and monthly flow charts react to the mid/extreme toggle in the following ways:

• In "extremes" mode, the hydrography shows the max/mean/min values across all CMIP5 models and scenarios (excluding RCP 2.6). In "mid" mode, it shows the max/mean/min across all CMIP5 models for just the RCP 6.0 scenario.
• In "extremes" mode, the monthly flow chart shows box plots populated with an array of values across all CMIP5 models and scenarios (excluding RCP 2.6). In "mid" mode, it shows a single mean value for each month (i.e., just a scatter marker, not a boxplot) which represents the mean value across all CMIP5 models for the RCP 6.0 scenario.

Testing is a little tricky since the StatsTable code hasn't been updated to work with the new API response structure in this branch, causing the report page to not to load properly. To run this branch, you'll need to comment out all references to the StatsTable component. I.e., comment out every line like this in Report.vue to test:

<StatsTable ... />

[Copilot]

Pull request overview

Updates the hydrology report visualizations to respond to the “mid” vs “extremes” toggle, aligning chart outputs with the updated Data API hydroviz response shape.

Changes:

• Update hydroviz API request URL to remove the hard-coded model segment.
• Make Hydrograph use projected[appContext] to render mid vs extremes data.
• Make Monthly Flow render boxplots for extremes and single-point monthly means for mid.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
webapp/stores/streamSegment.ts	Updates hydroviz endpoint URL format to match the new API structure.
webapp/components/Viz/MonthlyFlow.vue	Rebuilds monthly flow chart based on app context (extremes boxplots vs mid scatter).
webapp/components/Viz/Hydrograph.vue	Switches projected hydrograph data source based on app context.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[Copilot]

@cstephen I've opened a new pull request, #130, to work on those changes. Once the pull request is ready, I'll request review from you.