Add tri-state checkbox for bulk PR selection/deselection

[Copilot]

Users had no way to select or deselect all PRs at once, requiring individual checkbox clicks for each PR.

Changes

• UI: Added TriStateCheckbox to PR list header with dynamic label ("Select all" / "Deselect all")

  • Computed state from filteredPrs count vs selectedPrIds intersection
  • States: On (all selected), Off (none selected), Indeterminate (partial selection)

• ViewModel: Added deselectAllPrs() to clear selectedPrIds set

  • Complements existing selectAllPrs(available: Set<String>)

• Behavior: Clicking when Off or Indeterminate selects all filtered PRs; clicking when On deselects all

State computation

private fun computeSelectAllState(
    filteredPrs: List<PullRequest>,
    selectedPrIds: Set<String>,
): ToggleableState {
    if (filteredPrs.isEmpty()) return ToggleableState.Off
    
    val selectedCount = filteredPrs.count { selectedPrIds.contains(it.id) }
    return when {
        selectedCount == 0 -> ToggleableState.Off
        selectedCount == filteredPrs.size -> ToggleableState.On
        else -> ToggleableState.Indeterminate
    }
}

The checkbox updates automatically when individual PR checkboxes change, maintaining consistency with the existing selection model where empty selectedPrIds means "all selected".

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• dl.google.com
  • Triggering command: /usr/lib/jvm/temurin-17-jdk-amd64/bin/java /usr/lib/jvm/temurin-17-jdk-amd64/bin/java --add-opens=java.base/java.lang=ALL-UNNAMED --add-opens=java.base/java.lang.invoke=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.api=ALL-UNNAMED --add-exports=jdk.compiler/com.sun.tools.javac.util=ALL-UNNAMED --add-opens=java.base/java.util=ALL-UNNAMED --add-opens=java.prefs/java.util.prefs=ALL-UNNAMED --add-opens=java.base/java.nio.charset=ALL-UNNAMED --add-opens=java.base/java.net=ALL-UNNAMED --add-opens=java.base/java.util.concurrent.atomic=ALL-UNNAMED --add-opens=java.xml/javax.xml.namespace=ALL-UNNAMED -Xmx3072M -Dfile.encoding=UTF-8 -Duser.country -Duser.language=en -Duser.variant -cp /home/REDACTED/.gradle/wrapper/dists/gradle-8.14.3-bin/cv11ve7ro1n3o1j4so8xd9n66/gradle-8.14.3/lib/gradle-daemon-main-8.14.3.jar (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>3 state buttonでprを全選択・全選択解除できるようにする</issue_title>
<issue_description></issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes 3 state buttonでprを全選択・全選択解除できるようにする #114

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