Phase 7 & 8: Routes optimization refactor and request utils split

Phase 7 - Optimization handlers:
- Create api/optimization_handlers.py with try_prefix_detection,
  try_quota_mock, try_title_skip, try_suggestion_skip, try_filepath_mock
- Add try_optimizations() that runs handlers in order
- Refactor routes.create_message to use try_optimizations()
- Update test_routes_optimizations patch targets

Phase 8 - Request utils split:
- Create api/detection.py: is_quota_check_request, is_title_generation_request,
  is_prefix_detection_request, is_suggestion_mode_request,
  is_filepath_extraction_request
- Create api/command_utils.py: extract_command_prefix, extract_filepaths_from_command
- Slim request_utils.py to get_token_count + re-exports for backward compat

Co-authored-by: Ali Khokhar <alishahryar2@gmail.com>

api/command_utils.py

@@ -0,0 +1,139 @@
+"""Command parsing utilities for API optimizations."""
+
+import shlex
+
+
+def extract_command_prefix(command: str) -> str:
+    """Extract the command prefix for fast prefix detection.
+
+    Parses a shell command safely, handling environment variables and
+    command injection attempts. Returns the command prefix suitable
+    for quick identification.
+
+    Returns:
+        Command prefix (e.g., "git", "git commit", "npm install")
+        or "none" if no valid command found
+    """
+    if "`" in command or "$(" in command:
+        return "command_injection_detected"
+
+    try:
+        parts = shlex.split(command, posix=False)
+        if not parts:
+            return "none"
+
+        env_prefix = []
+        cmd_start = 0
+        for i, part in enumerate(parts):
+            if "=" in part and not part.startswith("-"):
+                env_prefix.append(part)
+                cmd_start = i + 1
+            else:
+                break
+
+        if cmd_start >= len(parts):
+            return "none"
+
+        cmd_parts = parts[cmd_start:]
+        if not cmd_parts:
+            return "none"
+
+        first_word = cmd_parts[0]
+        two_word_commands = {
+            "git",
+            "npm",
+            "docker",
+            "kubectl",
+            "cargo",
+            "go",
+            "pip",
+            "yarn",
+        }
+
+        if first_word in two_word_commands and len(cmd_parts) > 1:
+            second_word = cmd_parts[1]
+            if not second_word.startswith("-"):
+                return f"{first_word} {second_word}"
+            return first_word
+        return first_word if not env_prefix else " ".join(env_prefix) + " " + first_word
+
+    except ValueError:
+        return command.split()[0] if command.split() else "none"
+
+
+def extract_filepaths_from_command(command: str, output: str) -> str:
+    """Extract file paths from a command locally without API call.
+
+    Determines if the command reads file contents and extracts paths accordingly.
+    Commands like ls/dir/find just list files, so return empty.
+    Commands like cat/head/tail actually read contents, so extract the file path.
+
+    Returns:
+        Filepath extraction result in <filepaths> format
+    """
+    listing_commands = {
+        "ls",
+        "dir",
+        "find",
+        "tree",
+        "pwd",
+        "cd",
+        "mkdir",
+        "rmdir",
+        "rm",
+    }
+
+    reading_commands = {"cat", "head", "tail", "less", "more", "bat", "type"}
+
+    try:
+        parts = shlex.split(command, posix=False)
+        if not parts:
+            return "<filepaths>\n</filepaths>"
+
+        base_cmd = parts[0].split("/")[-1].split("\\")[-1].lower()
+
+        if base_cmd in listing_commands:
+            return "<filepaths>\n</filepaths>"
+
+        if base_cmd in reading_commands:
+            filepaths = []
+            for part in parts[1:]:
+                if part.startswith("-"):
+                    continue
+                filepaths.append(part)
+
+            if filepaths:
+                paths_str = "\n".join(filepaths)
+                return f"<filepaths>\n{paths_str}\n</filepaths>"
+            return "<filepaths>\n</filepaths>"
+
+        if base_cmd == "grep":
+            flags_with_args = {"-e", "-f", "-m", "-A", "-B", "-C"}
+            pattern_provided_via_flag = False
+            positional: list[str] = []
+
+            skip_next = False
+            for part in parts[1:]:
+                if skip_next:
+                    skip_next = False
+                    continue
+
+                if part.startswith("-"):
+                    if part in flags_with_args:
+                        if part in {"-e", "-f"}:
+                            pattern_provided_via_flag = True
+                        skip_next = True
+                    continue
+
+                positional.append(part)
+
+            filepaths = positional if pattern_provided_via_flag else positional[1:]
+            if filepaths:
+                paths_str = "\n".join(filepaths)
+                return f"<filepaths>\n{paths_str}\n</filepaths>"
+            return "<filepaths>\n</filepaths>"
+
+        return "<filepaths>\n</filepaths>"
+
+    except Exception:
+        return "<filepaths>\n</filepaths>"