fix(ai-vault): say OpenCode-in-WSL is not searchable from Windows yet (#20971)

The scan issue for an OpenCode database on a \\wsl.localhost share read as an
error with an instruction the user cannot follow. It now surfaces on the Agent
Session Search settings page under a computer row, where it belongs as a known
limitation, so the WSL branch now reads 'OpenCode sessions inside WSL can't be
searched from Windows yet.'

Copy only: the issue keeps kind 'scope' and its path, every other branch is
untouched, and discovery, the WSL gate, and the busy-timeout behavior are
unchanged.

src/main/ai-vault/session-scanner-opencode-sqlite-open.test.ts

@@ -250,14 +250,13 @@ describe('openCodeBusyTimeoutMs', () => {
 describe('openCodeDatabaseScanIssue', () => {
   const cantOpen = Object.assign(new Error('unable to open database file'), { errcode: 14 })
 
-  it('names the wal-index over a WSL share rather than repeating the driver string', () => {
-    const issue = openCodeDatabaseScanIssue(
-      '\\\\wsl.localhost\\Ubuntu\\home\\ada\\.local\\share\\opencode\\opencode.db',
-      cantOpen
-    )
+  it('states the WSL share as a known limitation rather than an error to act on', () => {
+    const dbPath = '\\\\wsl.localhost\\Ubuntu\\home\\ada\\.local\\share\\opencode\\opencode.db'
+    const issue = openCodeDatabaseScanIssue(dbPath, cantOpen)
 
     expect(issue.kind).toBe('scope')
-    expect(issue.message).toContain('\\\\wsl.localhost')
+    expect(issue.path).toBe(dbPath)
+    expect(issue.message).toBe("OpenCode sessions inside WSL can't be searched from Windows yet.")
     // Checkpointing cannot fix a share that refuses SQLite's locks, so the copy
     // must not send the user after the write-ahead log.
     expect(issue.message).not.toContain('write-ahead log')
@@ -282,7 +281,7 @@ describe('openCodeDatabaseScanIssue', () => {
     )
 
     expect(issue.message).not.toContain('is writing to')
-    expect(issue.message).toContain('inside the distro')
+    expect(issue.message).toBe("OpenCode sessions inside WSL can't be searched from Windows yet.")
   })
 
   it('still blames a live writer for the same error on a local path', () => {

src/main/ai-vault/session-scanner-opencode-sqlite-open.ts

@@ -99,16 +99,15 @@ export function openCodeDatabaseScanIssue(dbPath: string, error: unknown): AiVau
       ? `OpenCode is writing to ${name} right now, so its history was skipped. It is read again on the next refresh.`
       : kind === 'unreadable'
         ? `OpenCode history in ${name} could not be read: ${errorMessage(error)}`
-        : `OpenCode history in ${name} could not be read. ${unreadableShareAdvice(dbPath)}`
+        : unreadableShareDetail(dbPath, name)
   return { agent: 'opencode', kind: 'scope', path: dbPath, message: detail }
 }
 
-function unreadableShareAdvice(dbPath: string): string {
-  // Named only when the evidence supports it; a generic share gets generic copy.
-  // Deliberately not "flush the write-ahead log": checkpointing changes nothing
-  // here, and telling the user to try it would send them after a fix that cannot
-  // work. The share itself is the blocker.
+function unreadableShareDetail(dbPath: string, name: string): string {
+  // A known limitation, not a failure the user can act on: nothing they do on
+  // the Windows side makes the share hand out SQLite's locks. Deliberately not
+  // "flush the write-ahead log" either — checkpointing changes nothing here.
   return isWslUncPath(dbPath)
-    ? 'Windows cannot open SQLite databases over the \\\\wsl.localhost share, so this history has to be read from inside the distro.'
-    : 'Its write-ahead log cannot be opened read-only on this filesystem. Exit OpenCode cleanly to flush the log.'
+    ? "OpenCode sessions inside WSL can't be searched from Windows yet."
+    : `OpenCode history in ${name} could not be read. Its write-ahead log cannot be opened read-only on this filesystem. Exit OpenCode cleanly to flush the log.`
 }