🎨 Palette: Improve Team Lab unit selection with native constraints

[Gunnarguy]

💡 What: Replaced manual warning and list truncation with Streamlit's native max_selections=4 argument in the "Team Lab" st.multiselect. Also added a helpful placeholder and updated help text.
🎯 Why: Previously, users could select an unlimited number of units, only to receive a warning banner and have their selection silently truncated. The native max_selections argument prevents invalid selections from the start, providing immediate, accessible feedback. The placeholder adds clarity to an empty state.
📸 Before/After: The multiselect now says "Select units..." when empty, natively prevents more than 4 items from being chosen, and has a native '?' tooltip icon for additional context.
♿ Accessibility: Streamlit's native multi-select limitation provides better immediate constraint feedback compared to a post-action warning banner.

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PR created automatically by Jules for task 10531238304413317721 started by @Gunnarguy

Summary by Sourcery

Enforce native selection limits and improve empty-state guidance in the Team Lab multiselect UI, while documenting the design decision in the Palette notes.

New Features:

• Use Streamlit's native max_selections constraint on the Team Lab unit multiselect to cap selections at four.
• Add a placeholder prompt and streamlined help text to clarify how to select units in the Team Lab view.

Enhancements:

• Remove manual post-selection truncation logic and warning banner in favor of native multiselect constraints.
• Document best practices for enforcing input limits with Streamlit native parameters in the Palette guidelines.

Chores:

• Update processed leaderboard CSV artifacts and add a Streamlit log file to the repository.

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[sourcery-ai]

Reviewer's guide (collapsed on small PRs)

Reviewer's Guide

This PR updates the Team Lab multiselect to use Streamlit’s native selection limit and improves the empty-state and guidance UX, while adding a corresponding design-learning entry in the Jules palette documentation and touching leaderboard data/log files.

Sequence diagram for updated Team Lab unit selection constraints

sequenceDiagram
  actor User
  participant StreamlitApp
  participant render_team_lab
  participant st_multiselect
  participant st_info

  User ->> StreamlitApp: open TeamLab
  StreamlitApp ->> render_team_lab: render_team_lab(data)
  render_team_lab ->> st_multiselect: st.multiselect(label, options, format_func, max_selections, placeholder, help)

  alt [user selects more than 4 units]
    User ->> st_multiselect: select_units
    st_multiselect ->> User: enforce max_selections=4
  else [user selects 0 units]
    render_team_lab ->> st_info: st.info("Select up to 4 units to inspect SP economy and defensive coverage.")
  else [user selects 1-4 units]
    render_team_lab ->> render_team_lab: analyze selected_variant_ids
  end

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File-Level Changes

Change	Details	Files
Use Streamlit’s native multiselect constraints and improve Team Lab unit selection UX.	Replaced manual selection length checking and truncation with the multiselect max_selections parameter set to 4. Updated the multiselect help text to reflect the enforced limit without mentioning truncation. Added a placeholder to clarify the empty multiselect state. Removed the warning banner logic that previously appeared when more than 4 units were selected. Kept the existing empty-state info banner for when no units are selected.	src/grandchase_meta_analyzer/explorer_app.py
Document the UX learning about native input limits in the palette guide.	Added a dated section describing the drawback of manual selection validation for Streamlit multiselect. Recorded the recommendation to use native max_selections over custom warning banners for better feedback.	.Jules/palette.md
Update processed leaderboard data and add a Streamlit log artifact.	Modified the processed hero leaderboard data file (content changes not shown in diff snippet). Modified the processed variant leaderboard data file (content changes not shown in diff snippet). Added or updated a Streamlit log file in the repository.	data/processed/hero_leaderboard.csv data/processed/variant_leaderboard.csv streamlit.log

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[sourcery-ai]

Hey - I've left some high level feedback:

• It looks like streamlit.log was added to the repo; this file should typically be excluded (e.g., via .gitignore) rather than committed as part of the PR.

Prompt for AI Agents

Please address the comments from this code review:

## Overall Comments
- It looks like `streamlit.log` was added to the repo; this file should typically be excluded (e.g., via `.gitignore`) rather than committed as part of the PR.

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[Copilot]

Pull request overview

This PR improves the Streamlit “Team Lab” unit multiselect UX by enforcing the 4-unit limit via Streamlit’s native max_selections constraint (instead of post-selection truncation), and documents the design rationale in the Palette notes. It also includes updates to processed leaderboard CSV artifacts and adds a streamlit.log file.

Changes:

• Enforce “max 4 units” directly in the Team Lab st.multiselect, plus add a placeholder and simplify help text.
• Document the “prefer native Streamlit constraints” guideline in .Jules/palette.md.
• Update data/processed/*_leaderboard.csv artifacts and add streamlit.log (these artifact/log changes need attention before approval).

Reviewed changes

Copilot reviewed 4 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/grandchase_meta_analyzer/explorer_app.py	Replaces manual post-selection truncation/warning with Streamlit-native max_selections=4, plus placeholder/help tweaks.
.Jules/palette.md	Adds a Palette note recommending native Streamlit input constraints like max_selections.
data/processed/variant_leaderboard.csv	Updates processed variant leaderboard artifact (currently appears to have lost data and shifted rankings significantly).
data/processed/hero_leaderboard.csv	Updates processed hero leaderboard artifact (currently appears to have placeholder-like uniform scores and missing name_ko).
streamlit.log	Adds a runtime log containing stack traces and network/external URLs (should not be committed).