Add Codex clear and compact slash commands (#541)

* Add Codex clear and compact slash commands

* Stabilize queued thinking event test

* Interrupt active Codex turn before slash commands

web/src/lib/codexSlashCommands.test.ts

@@ -1,9 +1,16 @@
 import { describe, expect, it } from 'vitest'
-import { findUnsupportedCodexBuiltinSlashCommand, getBuiltinSlashCommands } from './codexSlashCommands'
+import {
+    findCodexCustomPromptExpansion,
+    findUnsupportedCodexBuiltinSlashCommand,
+    getBuiltinSlashCommands,
+    mergeSlashCommands
+} from './codexSlashCommands'
 
 describe('getBuiltinSlashCommands', () => {
     it('exposes HAPI-supported codex built-ins in remote web mode', () => {
         expect(getBuiltinSlashCommands('codex').map((command) => command.name)).toEqual(expect.arrayContaining([
+            'clear',
+            'compact',
             'plan',
             'status',
             'execute',
@@ -13,6 +20,41 @@ describe('getBuiltinSlashCommands', () => {
     })
 })
 
+describe('mergeSlashCommands', () => {
+    it('lets custom commands override same-name built-ins', () => {
+        const commands = mergeSlashCommands([
+            { name: 'clear', source: 'builtin' },
+            { name: 'compact', source: 'builtin' },
+            { name: 'clear', source: 'project', content: 'project clear prompt' }
+        ])
+
+        expect(commands).toEqual([
+            { name: 'compact', source: 'builtin' },
+            { name: 'clear', source: 'project', content: 'project clear prompt' }
+        ])
+    })
+})
+
+describe('findCodexCustomPromptExpansion', () => {
+    it('expands exact custom codex prompt commands', () => {
+        expect(findCodexCustomPromptExpansion('  /clear  ', [
+            { name: 'clear', source: 'builtin' },
+            { name: 'clear', source: 'project', content: 'custom clear prompt' }
+        ])).toBe('custom clear prompt')
+    })
+
+    it('ignores built-ins and commands with arguments', () => {
+        const commands = [
+            { name: 'compact', source: 'project', content: 'custom compact prompt' }
+        ] as const
+
+        expect(findCodexCustomPromptExpansion('/compact now', commands)).toBeNull()
+        expect(findCodexCustomPromptExpansion('/clear', [
+            { name: 'clear', source: 'builtin' }
+        ])).toBeNull()
+    })
+})
+
 describe('findUnsupportedCodexBuiltinSlashCommand', () => {
     it('detects unsupported codex built-ins', () => {
         expect(findUnsupportedCodexBuiltinSlashCommand('  /diff ', [])).toBe('diff')