api/internal: invalidate SystemInfoCache on domain-add and domain-delete

[alex-schose]

SystemInfoCache invalidates cls.cache for every event in vm_events
(via event_handler), but on_domain_add and on_domain_delete only
register / unregister the per-VM handlers - they never invalidate the cache
itself, and vm_events contains neither domain-add nor domain-delete.

As a result a freshly-created (or freshly-deleted) VM is missing from / stale
in the cached system_info until some other event happens to invalidate it.
While stale, qubes-qrexec-policy-daemon's internal.GetSystemInfo query
returns the old snapshot: a call naming a new VM logs
target '...' does not exist, using @default instead, and a deleted VM can
still be offered by a @default ask handler (e.g. qvm-copy).

Fix: invalidate the cache in both handlers, after (un)registering the per-VM
handlers. domain-add / domain-delete are app-level events; this is the
symmetric counterpart to how every vm_events entry already invalidates via
event_handler. Performance impact is negligible - these events are
infrequent relative to the per-VM events that already clear the cache.

Fixes QubesOS/qubes-issues#10911.

[marmarek]

PipelineRefresh

[marmarek]

PipelineRetry

[codecov]

Codecov Report

❌ Patch coverage is 0% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 70.35%. Comparing base (ccb5513) to head (01972b6).

Files with missing lines	Patch %	Lines
qubes/api/internal.py	0.00%	2 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #825      +/-   ##
==========================================
- Coverage   70.46%   70.35%   -0.12%     
==========================================
  Files          61       61              
  Lines       14144    14087      -57     
==========================================
- Hits         9967     9911      -56     
+ Misses       4177     4176       -1     

Flag	Coverage Δ
unittests	70.35% <0.00%> (-0.12%)	⬇️

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[andrewdavidwong]

Fixes #10911.

You must add QubesOS/qubes-issues in front of #10911 because it's a different repo. The whole thing should look like this: Fixes QubesOS/qubes-issues#10911.

[alex-schose]

Done — updated to Fixes QubesOS/qubes-issues#10911.