Clear installed scan state after scan failures

[kitsuyui]

Summary

Clear installed scan state after scan failures

Centralize installed-app scan finalization so the Installed page always
receives set-scanning-for-installed(false), even when scanning rejects.
Keep the existing IPC error dialog path unchanged and cover the shared scan
lifecycle with a focused regression test.

Chosen fix

• approach: structural-centralize-installed-scan-finalization
  The observed bug is a missing failure-side state reset, but the safest minimal fix is to centralize scan finalization where scan lifecycle already starts (clean-app-management) instead of patching only the IPC catch block. That removes the split-brain ownership where success clears scanning in one file and failure would clear it in another, while keeping scope limited to the installed-app scan path and avoiding any repo-policy conflicts.

[github-actions]

gh-counter

PR gate

	Removed	Added	+/-
TODO/FIXME	0	0	0
Type escape	0	0	0
Lint suppression	0	0	0
Electron webPreferences risk	0	0	0

Repo dashboard

	main (a03e5b6)	#88 (b93fd23)	+/-
TODO/FIXME	0	0	0
Type escape	1	1	0
Lint suppression	36	36	0
Electron webPreferences risk	0	0	0

---

Reported by gh-counter

[github-actions]

Code Metrics Report

	main (a03e5b6)	#88 (b93fd23)	+/-
Coverage	41.1%	41.4%	+0.2%
Code to Test Ratio	1:0.3	1:0.3	+0.0
Test Execution Time	7s	7s	0s

Details

  |                     | main (a03e5b6) | #88 (b93fd23) |  +/-  |
  |---------------------|----------------|---------------|-------|
+ | Coverage            |          41.1% |         41.4% | +0.2% |
  |   Files             |            146 |           147 |    +1 |
  |   Lines             |           2578 |          2582 |    +4 |
+ |   Covered           |           1061 |          1069 |    +8 |
+ | Code to Test Ratio  |          1:0.3 |         1:0.3 |  +0.0 |
  |   Code              |          13389 |         13440 |   +51 |
+ |   Test              |           4299 |          4332 |   +33 |
  | Test Execution Time |             7s |            7s |    0s |

Code coverage of files in pull request scope (0.0% → 44.4%)

Files	Coverage	+/-	Status
main-src/libs/app-management/get-installed-apps-async.ts	0.0%	0.0%	modified
main-src/libs/app-management/installed-app-scan.ts	100.0%	+100.0%	added

---

Reported by octocov