fix(fish): drop a repeated shim from PATH even when a copy is already first

The $PATH[1] guard treated the shim's front position as proof there was
nothing to do, so a PATH carrying the shim both first and later kept the
later copy. Filter unconditionally, then prepend.

Co-authored-by: Orca <help@stably.ai>

src/main/fish-startup-environment.node-pty.test.ts

@@ -245,4 +245,42 @@ describe('fish startup environment', () => {
       rmSync(home, { recursive: true, force: true })
     }
   })
+
+  itWithFish('drops a repeated shim even when a copy is already first in PATH', () => {
+    // Why: guarding on `$PATH[1]` alone would take the shim's front position as proof
+    // there is nothing to do and leave the later copy in place.
+    const home = mkdtempSync(join(tmpdir(), 'orca fish dedupe '))
+    try {
+      const initPath = join(home, 'init.fish')
+      writeFileSync(initPath, getFishInitCommand(SHELL_READY_MARKER))
+      const result = spawnSync(
+        FISH.path as string,
+        [
+          '--no-config',
+          '-c',
+          [
+            `set -gx PATH ${fishQuote(SHIM_DIR)} /usr/bin /bin ${fishQuote(SHIM_DIR)}`,
+            `source ${fishQuote(initPath)}`,
+            'for __probe_entry in $PATH; echo "PATH=$__probe_entry"; end'
+          ].join('\n')
+        ],
+        {
+          encoding: 'utf8',
+          env: {
+            PATH: process.env.PATH ?? '/usr/bin:/bin',
+            HOME: home,
+            ORCA_ATTRIBUTION_SHIM_DIR: SHIM_DIR,
+            ORCA_SHELL_READY_MARKER: '0'
+          }
+        }
+      )
+
+      expect(result.stderr).toBe('')
+      expect(result.status).toBe(0)
+      const pathEntries = [...result.stdout.matchAll(/^PATH=(.*)$/gm)].map((match) => match[1])
+      expect(pathEntries).toEqual([SHIM_DIR, '/usr/bin', '/bin'])
+    } finally {
+      rmSync(home, { recursive: true, force: true })
+    }
+  })
 })

src/main/shell-templates.ts

@@ -183,7 +183,7 @@ end`
 /**
  * Everything Orca must apply to a fish session *after* the user's own startup
  * files, delivered as one `--init-command` (fish evaluates -C after config.fish
- * and conf.d, and multi-`-C` support varies by version).
+ * and conf.d).
  *
  * The POSIX wrappers do this from their rc files; fish has no such hook, so
  * without this a fish pane silently loses both halves of the contract.
@@ -200,10 +200,11 @@ export function getFishInitCommand(escapedMarker: string): string {
   # of the user's session. Order matches the POSIX wrappers: attribution, then teams,
   # and the relay's own shim (ORCA_REMOTE_CLI_BIN_DIR) last so it ends up first.
   for __orca_shim_dir in $ORCA_ATTRIBUTION_SHIM_DIR $ORCA_AGENT_TEAMS_SHIM_DIR $ORCA_REMOTE_CLI_BIN_DIR
-    if test -n "$__orca_shim_dir"; and test "$PATH[1]" != "$__orca_shim_dir"
-      # Why drop existing copies instead of a plain prepend: this text can run twice in
-      # one session (a re-initialized pane), and a plain prepend grows PATH by one
-      # duplicate per shim per run. Filtered by string compare, not \`string match\`,
+    if test -n "$__orca_shim_dir"
+      # Why filter unconditionally instead of skipping when the shim is already $PATH[1]:
+      # the shim can be first *and* repeated later, and that skip would keep the copy.
+      # Filter-then-prepend also makes a re-run a no-op, where a plain prepend would grow
+      # PATH by one duplicate per shim. Compared as strings, not with \`string match\`,
       # because a shim path may contain glob characters.
       set -l __orca_kept_path
       for __orca_path_entry in $PATH