feat(console): list/regex read_until, serial error clarity; v0.3

read_until:
- 'expected' now accepts a list of values (succeeds on any match).
- new 'regex: true' flag: each pattern is a Python regex (re.search over a
  bounded tail, Console.REGEX_WINDOW). Reports which pattern matched.

Serial console robustness & clarity:
- failed open() raises a clear ETUMRuntimeError ("Serial device '…' does not
  exist." / permission hint) instead of a raw pyserial traceback.
- a console whose open failed is safely "not open" (init _thd=None +
  isOpened guards in readchar/read_nowait/close) — no more cascading
  AttributeError: '_thd' on subsequent read steps.
- action handlers: one-liner for expected (ETUMRuntimeError) errors, full
  traceback kept for unexpected ones. All console errors use testium
  exceptions (ETUMRuntimeError).

Flatpak: grant --device=all so serial adapters (/dev/ttyUSB*, /dev/ttyACM*)
are visible in the sandbox.

Validation: new read_until list/regex (match + no-match) cases in
items/console/test.tum.

Version: 0.3.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

test/validation/items/console/test.tum

@@ -105,6 +105,46 @@
         - read_until: {expected: console_host_check_HOST, timeout: 5}
 {% endif %}
 
+# --- read_until matching a list of values (succeeds on any) ---
+- console:
+    name: Console read_until list match any
+    console_name: term
+    key: $(test)_PASS
+    steps:
+        - writeln: echo "list_marker_B"
+        - read_until: {expected: [list_marker_A, list_marker_B, list_marker_C], timeout: 5}
+
+- console:
+    name: Console read_until list no match
+    console_name: term
+    key: $(test)_FAIL
+    steps:
+        - read_until: {expected: [never_marker_A, never_marker_B], timeout: 1}
+
+# --- read_until with regular expressions ---
+- console:
+    name: Console read_until regex
+    console_name: term
+    key: $(test)_PASS
+    steps:
+        - writeln: echo "regex_val_4242_end"
+        - read_until: {expected: 'regex_val_\d+_end', regex: true, timeout: 5}
+
+- console:
+    name: Console read_until regex list any
+    console_name: term
+    key: $(test)_PASS
+    steps:
+        - writeln: echo "STATUS=ready"
+        - read_until: {expected: ['ERR:.*', 'STATUS=(ready|busy)'], regex: true, timeout: 5}
+
+- console:
+    name: Console read_until regex no match
+    console_name: term
+    key: $(test)_FAIL
+    steps:
+        - read_until: {expected: 'never_\d{4}', regex: true, timeout: 1}
+
 - console:
     name: Console closure
     execute_on_stop: true