fix(security): block all bare email tool names for non-admins; harden fence-tag regex

Review follow-up on #3681 (thanks @vgalin):

1. Routing bare email names made 10 of the 14 email tools executable by
   non-admin owners — is_public_blocked_tool() runs on the bare name
   before dispatch, and NON_ADMIN_BLOCKED_TOOLS only listed 4. Define the
   full email tool set once (BUILTIN_EMAIL_TOOLS in tool_security.py) and
   derive the blocklist, the fence tags (TOOL_TAGS), the bare-name
   dispatch, and the native-call mapping from it so they can't drift.
   This also fixes 4 tools (search_emails, draft_email, draft_email_reply,
   ai_draft_email_reply) that were missing from the old tool_schemas copy
   and therefore unreachable even for native function-calling models.

2. The relaxed fence regex from the previous commit could prefix-match
   longer fence tags: ```python3 parsed as tool "python" with content
   "3\nprint(...)" and executed as code. Add a (?![\w-]) boundary after
   the tag.

Tests: test_public_agent_policy_blocks_sensitive_tools now covers all 14
bare email names + the mcp__email__ form; new tests/test_fenced_inline_args.py
pins inline-args parsing, the python3/hyphenated-tag non-matches, and
strip/parse display mirroring.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/agent_tools/__init__.py

@@ -14,6 +14,7 @@ Sub-modules:
 import logging
 from collections import namedtuple
 
+from src.tool_security import BUILTIN_EMAIL_TOOLS
 from src.tool_utils import _truncate, get_mcp_manager, set_mcp_manager
 
 logger = logging.getLogger(__name__)
@@ -64,9 +65,10 @@ TOOL_TAGS = {"bash", "python", "web_search", "web_fetch", "read_file", "write_fi
              "manage_endpoints", "manage_mcp", "manage_webhooks",
              "manage_tokens", "manage_documents", "manage_settings",
              "manage_notes", "manage_calendar",
-             "resolve_contact", "manage_contact", "list_email_accounts", "send_email", "list_emails",
-             "read_email", "reply_to_email", "bulk_email", "archive_email",
-             "delete_email", "mark_email_read",
+             "resolve_contact", "manage_contact",
+             # Email tool names come from BUILTIN_EMAIL_TOOLS (unioned below)
+             # so the fence regex, dispatch, and non-admin blocklist all cover
+             # the same set.
              # Cookbook tools (LLM serving + downloads). Without these
              # entries, native function calls to e.g. list_served_models
              # are rejected as "Unknown function call" before reaching
@@ -83,7 +85,7 @@ TOOL_TAGS = {"bash", "python", "web_search", "web_fetch", "read_file", "write_fi
              # Generic loopback to any UI-button endpoint (cookbook,
              # gallery, email folders, etc.) — agent uses this when
              # there's no named tool wrapper for the action.
-             "app_api"}
+             "app_api"} | BUILTIN_EMAIL_TOOLS
 
 ToolBlock = namedtuple("ToolBlock", ["tool_type", "content"])