fix(integrations): declare kiro-cli multi-install safe (#3477)

* tidy kiro-cli multi-install-safe declaration + add docs row and test

kiro-cli is declared multi_install_safe (it uses a fully isolated .kiro/
root, .kiro/prompts command dir, a stable '.' separator, and a dedicated
manifest — #3471). main ended up with the flag assigned twice in the class
body; this drops the bare duplicate and keeps a single declaration with the
comment explaining why it's safe.

also adds the missing kiro-cli row to the multi-install-safe table in
docs/reference/integrations.md, and a test asserting the flag is set (the
registry contract tests already enforce the actual path isolation against
every other safe integration).

* address review: drop agent-file column and duplicate test

per maintainer guidance on #3477: the Isolation table listed each
integration's agent-context file (AGENTS.md, CLAUDE.md, etc.) alongside
its command dir, which contradicted the safety definition (Copilot flagged
kiro-cli/codex both mapping to AGENTS.md). those context files are owned by
the optional agent-context extension, not by multi_install_safe — the flag
governs only the command directory + manifest.

- renamed the column to 'Command directory' and removed the agent-file
  entries, so it lists only what each integration actually manages
- reworded the definition to note agent-context is a separate concern and
  is not multi-install safe
- removed the duplicate test_declared_multi_install_safe (the existing
  test_declares_multi_install_safe already asserts the same thing)

* address review: keep agent-root requirement; reframe agent-context targeting

- Restore 'static, unique agent root' alongside command directory in the
  multi-install-safe definition — base.py and test_registry.py
  (test_safe_integrations_have_distinct_agent_roots) enforce both.
- Reframe the agent-context note: multi_install_safe is an integration-level
  declaration about command/skill paths, so describe context-file targeting
  as independent of it rather than calling the extension 'not multi-install
  safe'. The extension can even sync multiple anchors via context_files.

* address review: hoist multi_install_safe to top of class

Move the multi_install_safe = True declaration to the top of
KiroCliIntegration (right after key) so it is visible at the exact spot
the diff touched. The flag was never actually removed — it was declared
once further down the class — but placing it at the top makes the opt-in
unmistakable in review and keeps the single declaration. Verified the
integration still resolves multi_install_safe is True; 24 kiro-cli tests
pass.

src/specify_cli/integrations/kiro_cli/__init__.py

@@ -13,6 +13,13 @@ _KIRO_ARG_FALLBACK = "(the user will provide the argument in this conversation)"
 
 class KiroCliIntegration(MarkdownIntegration):
     key = "kiro-cli"
+    # Kiro CLI keeps everything under a static, isolated agent root
+    # (``.kiro/`` with commands in ``.kiro/prompts``) that no other
+    # integration writes to, so it is safe to install alongside others
+    # (issue #3471). IntegrationBase defaults this to False; declaring it
+    # True here is the actual behavior change this integration opts into.
+    # The registry's multi-install-safe contract tests enforce that
+    # isolation for every integration setting this flag.
     multi_install_safe = True
     config = {
         "name": "Kiro CLI",
@@ -27,10 +34,3 @@ class KiroCliIntegration(MarkdownIntegration):
         "args": _KIRO_ARG_FALLBACK,
         "extension": ".md",
     }
-
-    # Kiro CLI keeps everything under a static, isolated agent root
-    # (``.kiro/`` with commands in ``.kiro/prompts``) that no other
-    # integration writes to, so it is safe to install alongside others
-    # (issue #3471). The registry's multi-install-safe contract tests
-    # enforce that isolation for every integration setting this flag.
-    multi_install_safe = True