lua and python bin detection rationalized: bins.py module created.

Added some api accessible from python and lua sub_processes. Now the tests only access to py_func.tm instead of direct api.testium module access.

Corrected some f"xxx" to allow working with old python (bookworm).

Changed param.yaml of the test to allow lua to work in all situations.

Various other small fixes for frozen app, wheel.

Tested in all situations, and OK. Ready for tag !

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

CLAUDE.md

@@ -92,11 +92,33 @@ All dialog items (`dialog_image`, `dialog_question`, `dialog_references`, `dialo
 - Per-item log capture (`stdio_redir.read()`) is naturally race-free thanks to per-thread buffers (see `StdoutProxy`).
 
 ### Thread-aware stdout (`StdoutProxy`)
-`src/lib/stdout_redirect.py` — when `log_stored: True`, `intercept()` installs a `StdoutProxy` as `sys.stdout`/`sys.stderr` instead of a single shared `StringQueue`. The proxy:
+`src/testium/runtime/stdout_redirect.py` — when `log_stored: True`, `intercept()` installs a `StdoutProxy` as `sys.stdout`/`sys.stderr` instead of a single shared `StringQueue`. The proxy:
 - Holds one `StringQueue` per thread (registered via `register_thread(buffer=...)`). The main thread uses a default buffer; each parallel branch's thread registers its own at start and unregisters at end. `stdio_redir.read()` reads the calling thread's buffer → `addTest()` of an item running in branch X reads X's clean, non-interleaved output.
 - For the live stream (terminal in batch / GUI panel), prefixes every line emitted from a branch's thread with `[<branch_name>] ` so concurrent branches stay readable.
 - Exposes `write` / `writeln` / `flush` (Python 3.14's `unittest` calls `stream.writeln()` directly without `_WritelnDecorator`).
 
+### Subprocess API contract (py_func / lua_func)
+
+User test scripts running inside a `py_func` or `lua_func` subprocess **must** use the JSON-RPC bridge to interact with testium state:
+
+- Python: `import py_func.tm as tm` — auto-generates wrappers for every function in `runtime/api.py:SUPPORTED_API`. `tm.gd`/`tm.setgd`/`tm.delgd` go through JSON-RPC to the parent.
+- Lua: `local tm = require("tm")` — same idea on the Lua side.
+
+`api.testium` is the *main-process* implementation; it is **not** exposed to subprocesses by design (not bundled in PyInstaller, not on the subprocess `PYTHONPATH` in pip-installed mode either when isolation is preserved). An import attempt from a subprocess script is a code smell and is detected by `test/validation/items/isolation/`.
+
+To add a new API call usable from subprocesses:
+1. Add the function to `api/testium.py`
+2. Add its name to `SUPPORTED_API` in `runtime/api.py`
+3. It is auto-exposed via JSON-RPC by `interpreter/utils/api_srv.py` and auto-wrapped by `py_func/tm.py:_make_api`
+
+### External interpreter resolution (`bins.py`)
+`src/testium/interpreter/utils/bins.py` — single source of truth for the paths to the external Python and Lua interpreters used by subprocesses.
+
+- `python_bin()` / `lua_bin()` : resolve once, cache in memory. User can override via the `python_bin` / `lua_bin` global dict keys (typically populated from the YAML config). Falls back to discovery on PATH (candidates: `python3`/`python` and `lua`/`lua5.5`/`lua5.4`/`lua5.3`/`lua5.2`/`lua5.1`).
+- `ensure(*names)` : called by `TestSet._validate_runtime_deps()` at test load. Always requires `python` (the eval engine always runs); requires `lua` only if a `lua_func` item is in the tree. Fails fast with a clear error citing tried candidates and override key.
+
+Engines (`PyProcessBase`, `LuaProcessBase`, `EvalExecEngine`) call `bins.python_bin()`/`bins.lua_bin()` themselves — call sites never pass an explicit binary path.
+
 ## Key files
 
 | Path | Role |
@@ -161,23 +183,61 @@ Icons are assigned once when the test file is loaded (not updated live on theme
 
 The sub-test's own pass/fail result is intentionally not propagated.
 
+### Report exporters & plugins
+`src/testium/interpreter/test_report/test_report.py` — `_EXPORTER_REGISTRY` dict maps a format name (cmd key in the YAML `report.export`) to a lazy loader. Built-ins: `text`, `json`, `junit` (needs `junit_xml`), `html` (needs `lxml`). `sqlite` is the storage layer, no-op as an export.
+
+Third-party plugins are discovered at module import via `importlib.metadata.entry_points(group="testium.exporters")` — installing a wheel that declares such an entry point is enough, no testium config change needed:
+```toml
+[project.entry-points."testium.exporters"]
+my_format = "my_pkg:MyExporter"
+```
+Exporter contract: `__init__(self, name, con, path, pats, keys, no_header=False)` — the class does its work in `__init__` and writes to `path`.
+
+Behaviour on errors:
+- Unknown format → info line `[report] Export skipped: format "X" not found. Available: ...`, run continues.
+- Optional dependency missing → same info line with a pip-install hint, run continues.
+
+A real-world test plugin lives at `test/validation/fake_exporter/` (CSV exporter, auto-installed by `scripts/build_env.sh` and exercised by `test/validation/items/report_plugin/`).
+
+## Packaging
+
+Three distribution channels coexist, sharing the single `src/testium/` package:
+
+| Channel | Where | Notes |
+|---------|-------|-------|
+| Wheel (`pip install`) | `src/pyproject.toml` | Vanilla Python package; entry point `testium = "testium:main"` |
+| PyInstaller binary | `package/pyinstaller/` | Single ~130 MB binary. `py_func`, `runtime`, `lua_func` bundled at `_MEIPASS` root so the **host** Python can find them when launched as `python3 py_func`. `api`/`interpreter` are **not** exposed (subprocess isolation). |
+| Flatpak | `package/flatpak/` | (Existing recipe, not actively maintained in current refactor wave.) |
+
+The `.deb` work-in-progress lives in `package/deb/`:
+- `test_distro.sh debian:bookworm | debian:trixie | ubuntu:24.04` spins up a Docker/Podman container, reports system package availability, falls back to pip for what's missing (`pyside6` on bookworm/ubuntu, `telnetlib3`, `junit_xml`), runs the validation suite. Currently green on the three targets.
+
 ## Recent fixes / notable changes
-- `parallel` item: new item with `sync: all|any`, `wait_for`, daemon threads, `_stop_branch_recursively()`. Each branch thread registers a per-thread stdout buffer with `stdio_redir.register_thread(...)` so its log capture and live-output prefix work in isolation.
-- `parallel_branch` icon: distinct single-arrow icon (`parallel_branch.png`) separate from the parallel container's three-arrow icon.
-- `parallel` F1 panel: `steps` stripped from each branch dict so the panel shows per-branch attributes without duplicating the tree.
-- `test_item_container.py`: new `TestItemContainer` base class extracted from Group/Cycle patterns
-- `test_item_sleep.py`: interruptible loop (checks `self._is_stopped`) instead of blocking `time.sleep()` so `sync: any` can stop slow branches quickly
-- `stdout_redirect.py`: rewrote `intercept()` to install a `StdoutProxy` (thread-aware: per-thread capture buffers + branch-prefixed live output). Adds `writeln()` for Python 3.14 unittest compatibility.
-- `test_report.py`: `check_same_thread=False` + lock around the SQLite `INSERT` for parallel branch concurrency. Log capture itself is race-free thanks to per-thread buffers.
+- Restructure: single `src/testium/` Python package (was 4 sibling top-levels: `testium`, `lib`, `py_func`, `lua_func`). `lib/` → `runtime/`, `libs/` → `api/`. `pip install` now produces a clean `site-packages/testium/` with no top-level pollution; `.lua` files travel via `package_data`.
+- `bins.py`: centralised resolution + cache of external `python3` / `lua` binaries. Replaces the scattered `tm.gd("python_bin")`/`tm.gd("lua_bin")` dance and the duplicated discovery logic in `py_process.py`/`lua_process.py`. Validates at test load via `TestSet._validate_runtime_deps()` so missing interpreters fail fast.
+- Subprocess API contract: user scripts in `py_func`/`lua_func` use the JSON-RPC bridge (`py_func.tm` / Lua `tm`) — never `api.testium` / `interpreter.*` directly. `SUPPORTED_API` extended with `OS`, `get_main_dir`, `init_timestamp`, `timestamp`, `timestamp_as_sec` so subprocess scripts have the same surface as main-process code.
+- Report exporter plugin registry (`test_report.py`): `_EXPORTER_REGISTRY` + `entry_points("testium.exporters")` discovery. Missing format → info line, run continues.
+- About dialog rework: `QVBoxLayout` (resizable), version + dirty/branch info in a `QLabel` (auto-sized), copyright + clickable EUPL-1.2 link.
+- `test_ctrl.control()`: drain stale responses (left over from polled `loaded()` after `clear()` race) instead of failing on a wrong cmd key — fixes a "Unexpected return error in test set controller" seen in GUI mode after a fast reload.
+- `lua_process.py`: stderr no longer DEVNULL'd so actual Lua errors (missing `cjson`/`socket`) surface instead of "Connection refused".
+- `run_post_exec`: failure message uses `print_warn` (was `print_debug` — silent in non-debug runs).
+- Python 3.11 compat: replaced PEP 701 nested-quote f-strings (e.g. `f"... {d["k"]} ..."`) with single-quote inner strings or string concatenation.
+- `parallel` item: new item with `sync: all|any`, `wait_for`, daemon threads, `_stop_branch_recursively()`. Each branch thread registers a per-thread stdout buffer.
+- `parallel_branch` icon: distinct single-arrow icon (`parallel_branch.png`).
+- `parallel` F1 panel: `steps` stripped from each branch dict.
+- `test_item_container.py`: shared base class extracted from Group/Cycle.
+- `test_item_sleep.py`: interruptible loop so `sync: any` can stop slow branches quickly.
+- `stdout_redirect.py`: `StdoutProxy` (thread-aware buffers + branch-prefixed live output, `writeln()` for Python 3.14 unittest).
+- `test_report.py`: thread-safe SQLite INSERT for parallel branch concurrency.
 - `terminal.py`: deleted — `-m`/`--terminal` mode removed.
-- `batch.py`: premature loop exit when `gd_update` messages (no `"id"` key) were mistaken for the "finished" signal — fix: `"id" in m and m["id"] is None`
-- `batch.py`: `control("loaded")` deadlock if `TestProcess` crashed before `cmd_th` started — fix: daemon thread + `threading.Event` + `is_alive()` polling
-- `termlog.py`: `COLOR_DEFAULT = Fore.WHITE` invisible on light terminals; added auto-detection + light palette. Also fixed `write()` residue accumulation bug (`s[pos:]` → `s[pos+1:]`).
-- Dialog items: `auto_result`/`auto_value` now used in non-interactive text mode; dialogs without `auto_result` FAIL immediately in batch mode.
-- `run` item: renamed `tum_fime` → `tum`; removed `stdout=PIPE` (caused deadlock with `multiprocessing` spawn); result simplified to PASS on any completed subprocess.
-- `unittest` item: renamed from `unittest_file` (cmd key, display name, Python constant `TYPE_UNITTEST_FILE` → `TYPE_UNITTEST`).
-- GUI test tree: check and fold state preserved across same-file reloads (`test_file_manager.py`).
-- Licence: EUPL-1.2 (`LICENSE`, `CONTRIBUTING.md`, `pyproject.toml`).
+- `batch.py`: premature finish bug on `gd_update` (no `"id"` key) — fix uses `"id" in m and m["id"] is None`.
+- `batch.py`: `control("loaded")` deadlock on TestProcess crash — fix uses daemon thread + `threading.Event` + `is_alive()` polling.
+- `termlog.py`: light/dark terminal auto-detection (`COLORFGBG`, OSC 11) + write residue bug.
+- Dialog items: `auto_result`/`auto_value` for non-interactive text mode; dialogs without `auto_result` FAIL immediately in batch.
+- `run` item: renamed `tum_fime` → `tum`; removed `stdout=PIPE` deadlock; PASS on any completed subprocess.
+- `unittest` item: renamed from `unittest_file`.
+- GUI test tree: check and fold state preserved across same-file reloads.
+- Licence: EUPL-1.2.
 
 ## Validation tests
 Located in `test/validation/`. Run with `-b` flag: