ci: let the build be started by hand, not only by a pull request (#42)

Build PR ran on `pull_request` alone, and that turned out to be the only way to
get a build at all. When feat/block-storage conflicted with main on 2026-08-02
at 21:07 UTC, GitHub stopped being able to form refs/pull/39/merge, and with no
mergeable state no run was created -- not a failed one, not a skipped one, none.
Both open PRs sat without CI for fifteen hours and nothing in the UI said why.
The only workflow carrying workflow_dispatch was Benchmark, so there was no way
to ask for a build and watch it fail.

A manual trigger does not fix the conflict, but it makes the state visible
instead of silent.

force-build is tied to the event because the reusable workflow decides whether
to build from a dorny/paths-filter comparison, and that comparison has no base
outside a pull request. A run somebody started by hand is one they want
regardless of what changed, so it skips the filter rather than depending on
whatever the filter answers without a base. On a pull_request event the
expression is false and the path filter keeps deciding exactly as before.

Not verified yet, and it cannot be from a branch: GitHub reads workflow_dispatch
only from the default branch, so the button does not appear for this workflow
until this is merged. What to check afterwards is in the pull request.


Claude-Session: https://claude.ai/code/session_01NGpJqdmh7ZNH487GLqPJmK

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

Author: TheMeinerLP

.github/workflows/build-pr.yml

@@ -1,6 +1,8 @@
 name: Build PR
 
-on: [pull_request]
+on:
+  pull_request:
+  workflow_dispatch:
 
 permissions:
   contents: read
@@ -10,9 +12,15 @@ permissions:
 jobs:
   build:
     # Reuse the OneLiteFeather org build workflow (Java 25, OS matrix, tests, coverage).
+    #
+    # force-build on a manual run: the reusable workflow decides whether to build from a
+    # dorny/paths-filter comparison, and that comparison has no base outside a pull request. A
+    # manual run is one somebody asked for regardless of what changed, so it skips the filter
+    # instead of depending on what the filter would answer without a base.
     uses: OneLiteFeatherNET/workflows/.github/workflows/gradle-build-pr.yml@v2.4.0
     with:
       java-version: "25"
       java-distribution: "temurin"
       run-tests: true
+      force-build: ${{ github.event_name == 'workflow_dispatch' }}
     secrets: inherit