fix: revert unsafe permission changes from PR #78

Security fixes to restore defense-in-depth after merging PR #78:

**client.py:**
- Revert permission mode from "bypassPermissions" to "acceptEdits"
- Remove redundant web_tools_auto_approve_hook from PreToolUse hooks
- Remove unused import of web_tools_auto_approve_hook

**security.py:**
- Remove web_tools_auto_approve_hook function (was redundant and
  returned {} for ALL tools, not just WebFetch/WebSearch)

**server/services/spec_chat_session.py:**
- Restore allowed_tools restriction: [Read, Write, Edit, Glob,
  WebFetch, WebSearch]
- Revert permission mode from "bypassPermissions" to "acceptEdits"
- Keeps setting_sources=["project", "user"] for global skills access

**ui/src/components/AgentAvatar.tsx:**
- Remove unused getMascotName export to fix React Fast Refresh warning
- File now only exports AgentAvatar component as expected

The bypassPermissions mode combined with unrestricted tool access in
spec_chat_session.py created a security gap where Bash commands could
execute without validation (sandbox disabled, no bash_security_hook).

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

server/services/spec_chat_session.py

@@ -181,8 +181,15 @@ class SpecChatSession:
                     # System prompt loaded from CLAUDE.md via setting_sources
                     # Include "user" for global skills and subagents from ~/.claude/
                     setting_sources=["project", "user"],
-                    # No allowed_tools restriction - full access to all tools, skills, subagents
-                    permission_mode="bypassPermissions",  # Auto-approve all tools
+                    allowed_tools=[
+                        "Read",
+                        "Write",
+                        "Edit",
+                        "Glob",
+                        "WebFetch",
+                        "WebSearch",
+                    ],
+                    permission_mode="acceptEdits",  # Auto-approve file writes for spec creation
                     max_turns=100,
                     cwd=str(self.project_dir.resolve()),
                     settings=str(settings_file.resolve()),