Print out Workflows runner env vars

ci: allow cutting prereleases from branches (#936)

Adds prerelease machinery to test out changes without cutting a real
release. Needed for iterating quickly on AXL features without landing
questionable changes to main.

ci: allow cutting prereleases from branches (#936)

Adds prerelease machinery to test out changes without cutting a real
release. Needed for iterating quickly on AXL features without landing
questionable changes to main.

feat: support version.axl and remove config.toml (#935)

### Changes are visible to end-users: yes

- Searched for relevant documentation and updated as needed: yes
- Breaking change (forces users to change their own code or config): no
- Suggested release notes appear below: no

### Test plan
- Manual testing; please provide instructions so we can reproduce:
change the version.axl file and rerun `ASPECT_DEBUG=1
./target/debug/aspect` and observe the output.

revert some of the changes

Bump toolchains to remove patches (#931)

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### Changes are visible to end-users: yes/no

<!-- If no, please delete this section. -->

- Searched for relevant documentation and updated as needed: yes/no
- Breaking change (forces users to change their own code or config):
yes/no
- Suggested release notes appear below: yes/no

### Test plan

<!-- Delete any which do not apply -->

- Covered by existing test cases
- New test cases added
- Manual testing; please provide instructions so we can reproduce:

refactor: rip out the starlark-rust document generator (#929)

fix: drop all subscribers once stream is done (#928)

Bug: for event in build.build_events() would deadlock because:

1. recv() blocks waiting for channel disconnect
2. Channel disconnect only happens when senders are dropped
3. Senders are only dropped in join() called from wait()
4. wait() is called after the for loop exits — but the loop never exits

Fix: Added explicit close() method to Broadcaster that drops all senders
when the BES threadfinishes, triggering channel disconnect regardless of
when wait() is called.


With this change, now late subscriptions via `.build_events()` get
events replayed, the remaining build event sinks continue operate
without a replayer.

fix: drop all subscribers once stream is done (#928)

Bug: for event in build.build_events() would deadlock because:

1. recv() blocks waiting for channel disconnect
2. Channel disconnect only happens when senders are dropped
3. Senders are only dropped in join() called from wait()
4. wait() is called after the for loop exits — but the loop never exits

Fix: Added explicit close() method to Broadcaster that drops all senders
when the BES threadfinishes, triggering channel disconnect regardless of
when wait() is called.


With this change, now late subscriptions via `.build_events()` get
events replayed, the remaining build event sinks continue operate
without a replayer.

feat: axl add supports using tags with no releases (#927)