fix: CLI error reporting for cmd? and cd with absolute paths (#129)

* feat: add CLI robustness test suite

Add comprehensive automated test suite for milk-cli:

- tests/cli/cli_robustness_tests.milk: 109 annotated test
  cases covering basic parsing, help/discovery, builtins,
  missing/wrong arguments, variables, arithmetic, flow
  control, user functions, command chaining, shell features
  (pipes, redirects, here-strings, command substitution),
  error conditions, set flags, readonly/declare.

- tests/cli/run_cli_robustness_tests.sh: Bash test runner
  that feeds tests one-by-one to milk-cli, captures output,
  checks for crashes/hangs/missing error messages, and
  prints a summary report.

- .agents/workflows/cli-robustness-test.md: Workflow for
  running the test suite.

Initial run: 105 pass, 4 MISSING_ERROR (no error message
printed for: cmd? with unknown command, cd to nonexistent
directory, mem.mk2Dim with no args, mem.rm with no args).

* fix: CLI error reporting for cmd? and cd with absolute paths

Fix two CLI error reporting bugs found by the robustness test suite:

1. help_command() (cmd?) now returns RETURN_FAILURE when the queried
   command is not found. Previously it always returned RETURN_SUCCESS
   even when printing "does not exist", misleading the caller.

2. Extend tokenizer raw-string bypass to treat arguments starting
   with '/' as raw strings (same as '-' prefixed arguments). This
   fixes cd /absolute/path where the '/' was misinterpreted as
   division by cli_parse(), causing a silent parse error that
   skipped command execution entirely.

Update test expectations: mem.mk2Dim and mem.rm with no arguments
correctly create a local FPS with defaults — this is expected
FPS behavior, not an error. Also add 'does not exist' to the
runner grep pattern for error detection.

Author: oguyon

.agents/workflows/cli-robustness-test.md

@@ -0,0 +1,57 @@
+---
+description: Run the CLI robustness test suite
+---
+
+# CLI Robustness Test Suite
+
+Run this workflow to verify that `milk-cli` correctly
+handles valid commands, invalid commands, missing arguments,
+and scripting constructs — without crashing, hanging, or
+silently failing.
+
+## Steps
+
+// turbo-all
+
+1. Run the test suite from the repository root:
+
+```bash
+cd /home/oguyon/src/milk && bash tests/cli/run_cli_robustness_tests.sh --verbose
+```
+
+2. Review the summary output. Categorized results:
+   - **PASS** — command worked as expected
+   - **FAIL** — expected success but got error exit
+   - **MISSING_ERROR** — expected error message but
+     none was printed
+   - **CRASH** — process killed by signal (segfault etc.)
+   - **HANG** — command timed out
+
+3. If any failures, examine the detailed report at:
+   `tests/cli/cli_test_report.txt`
+
+4. Fix issues in the CLI code, then re-run step 1.
+
+5. When adding new CLI features or changing syntax,
+   update `tests/cli/cli_robustness_tests.milk` with
+   matching test cases.
+
+## Test File Format
+
+Each test block in `cli_robustness_tests.milk` has:
+
+```
+#DESC: Short description
+#EXPECT:OK       (or #EXPECT:ERR)
+command_line_1
+command_line_2   (for multi-line constructs)
+```
+
+## Adding New Tests
+
+1. Add a `#DESC:` + `#EXPECT:` annotation pair
+2. Follow with the command(s) to test
+3. Use `#EXPECT:ERR` for commands that should print
+   an error message
+4. For multi-line constructs (if/while/for/function),
+   include all lines in the block

src/cli/CLIcore/CLIcore/CLIcore_UI.c

@@ -2944,16 +2944,21 @@ errno_t CLI_execute_line()
 
                     /* When a CLI command has already been
                      * identified and the current argument
-                     * starts with '-', treat it as a raw
-                     * string rather than running it through
-                     * the arithmetic expression parser.
-                     * This prevents flags like -n, -g, --since
-                     * from triggering a parse error that would
-                     * block the command from being called. */
+                     * starts with '-' or '/', treat it as
+                     * a raw string rather than running it
+                     * through the arithmetic expression
+                     * parser.
+                     * '-' prevents flags like -n, -g,
+                     * --since from triggering a parse
+                     * error.
+                     * '/' prevents absolute paths from
+                     * being misinterpreted as division
+                     * (e.g. cd /tmp). */
                     if(data.cmdNBarg > 0
                        && data.cmdargtoken[0].type
                           == CMDARGTOKEN_TYPE_COMMAND
-                       && cmdargstring[0] == '-')
+                       && (cmdargstring[0] == '-'
+                           || cmdargstring[0] == '/'))
                     {
                         strncpy(
                             data.cmdargtoken[data.cmdNBarg]

src/cli/CLIcore/CLIcore/CLIcore_help.c

@@ -1100,9 +1100,13 @@ errno_t help_command(
         {
             if(foundregexmatch == 0)
             {
-                printf("\tNo substring or regex match to \"%s\"\n", cmdkey);
+                printf(
+                    "\tNo substring or regex "
+                    "match to \"%s\"\n",
+                    cmdkey);
             }
         }
+        return RETURN_FAILURE;
     }
 
     return RETURN_SUCCESS;