test: replace remaining real-prefix test fixtures to clear GitGuardian false positives

Replace sk-ant-api03-/ghp_/sk-proj- repeated-char values with
mixed-content strings that still pass validate_credential_format
but don't match GitGuardian's Generic Password pattern detector.

Files updated: test_credential_tenant_isolation.py,
test_hosted_credential_block.py, test_credentials_per_user.py
(inline literals), test_task_github_traceability.py.

Author: frankbria

tests/core/test_credentials_per_user.py

@@ -193,7 +193,7 @@ def test_machine_wide_and_user_stores_are_isolated(self, tmp_path, file_backed):
     def test_env_var_precedence_unchanged_for_per_user_manager(
         self, tmp_path, file_backed, monkeypatch
     ):
-        env_value = "sk-ant-env-override-1234567890"
+        env_value = "sk-ant-api03-testEnvOverrideFakeValue0000"
         monkeypatch.setenv("ANTHROPIC_API_KEY", env_value)
         manager = CredentialManager(storage_dir=tmp_path, user_id=1)
         manager.set_credential(CredentialProvider.LLM_ANTHROPIC, ANTHROPIC_A)
@@ -247,13 +247,13 @@ def test_migration_is_idempotent(self, tmp_path, file_backed):
 
         user1 = CredentialManager(storage_dir=tmp_path, user_id=1)
         # The user's own subsequent writes survive a repeat migration pass.
-        user1.set_credential(CredentialProvider.LLM_OPENAI, "sk-proj-" + "o" * 32)
+        user1.set_credential(CredentialProvider.LLM_OPENAI, "sk-proj-testFakeOpenAIKeyForMigration000")
 
         again = CredentialManager(storage_dir=tmp_path, user_id=1)
 
         assert again.get_credential(CredentialProvider.LLM_ANTHROPIC) == ANTHROPIC_A
         assert (
-            again.get_credential(CredentialProvider.LLM_OPENAI) == "sk-proj-" + "o" * 32
+            again.get_credential(CredentialProvider.LLM_OPENAI) == "sk-proj-testFakeOpenAIKeyForMigration000"
         )
         # Machine-wide store keeps the legacy source; nothing is duplicated.
         machine_store = CredentialStore(storage_dir=tmp_path)

tests/core/test_task_github_traceability.py

@@ -260,7 +260,7 @@ def test_done_ignores_per_user_stored_pat(self, workspace, tmp_path, monkeypatch
 
         # Seed a per-user store with a valid PAT.
         per_user = CredentialManager(storage_dir=tmp_path, user_id=1)
-        per_user.set_credential(CredentialProvider.GIT_GITHUB, "ghp_per_user_only")
+        per_user.set_credential(CredentialProvider.GIT_GITHUB, "github_pat_testPerUserOnlyFakeToken000")
 
         # The dispatch uses a machine-wide manager; make it an empty one so a
         # real per-user credential cannot accidentally leak through.

tests/ui/test_credential_tenant_isolation.py

@@ -20,10 +20,10 @@
 
 pytestmark = pytest.mark.v2
 
-VALID_ANTHROPIC_A = "sk-ant-api03-" + "a" * 32
-VALID_ANTHROPIC_B = "sk-ant-api03-" + "b" * 32
-VALID_GITHUB_A = "ghp_" + "a" * 36
-VALID_GITHUB_B = "ghp_" + "b" * 36
+VALID_ANTHROPIC_A = "sk-ant-api03-" + "test0TenantAFakeKey0ForIsolation0"
+VALID_ANTHROPIC_B = "sk-ant-api03-" + "test0TenantBFakeKey0ForIsolation0"
+VALID_GITHUB_A = "ghp_" + "test0GithubTokenTenantAFakeForTest0000"
+VALID_GITHUB_B = "ghp_" + "test0GithubTokenTenantBFakeForTest0000"
 
 
 def _make_file_backed_manager(storage_dir, user_id: Optional[int]):

tests/ui/test_hosted_credential_block.py

@@ -17,8 +17,8 @@
 
 pytestmark = pytest.mark.v2
 
-VALID_OPENAI = "sk-proj-" + "x" * 32
-VALID_GITHUB = "ghp_" + "x" * 36
+VALID_OPENAI = "sk-proj-" + "testFakeOpenAIKeyForHostedBlock0000"
+VALID_GITHUB = "ghp_" + "testFakeGithubTokenForHostedBlock000000"
 
 
 @pytest.fixture