M4: fetch mode, cleanup and documentation

- --fetch with a Jinja-subset renderer and the shipped templates
- clippy clean, cargo fmt, all tests green
- README status and differential testing instructions

README.md

@@ -7,24 +7,60 @@ This project is a drop-in replacement for the **standalone** Glances modes:
 
 - curses-like terminal UI (`glances`)
 - stdout modes: `--stdout`, `--stdout-csv`, `--stdout-json`
-- `--fetch`, `--issue`, `--modules-list`
-- all plugins, including extended ones (containers, GPUs, sensors, ...)
-- the same `glances.conf` configuration file
+- `--fetch` (with the shipped templates), `--issue`, `--module-list`
+- the same `glances.conf` configuration file (limits, thresholds, aliases,
+  show/hide lists, per-plugin refresh, history, actions)
+- compatible stats schemas and CLI flags for the implemented features
 
 The following Python Glances features are intentionally **not** provided:
-REST API, WebUI, MCP, client/server mode, discovery/browser, SNMP and exporters.
+REST API, WebUI, MCP, client/server mode, discovery/browser, SNMP and
+exporters.
 
 ## Status
 
-Work in progress. See the milestones in the project plan; the workspace is
-organized as:
+| Area | Status |
+| --- | --- |
+| CLI (clap, drop-in flags) | done |
+| Configuration (`glances.conf`) | done |
+| Plugin model (limits, views, rates, MMM, history, events, actions) | done |
+| Terminal UI (ratatui) | done |
+| stdout / CSV / JSON / fetch / issue modes | done |
+| Core plugins | cpu, percpu, mem, memswap, load, fs, network, diskio, sensors, irq, system, uptime, now, core, version, psutilversion, quicklook, processcount, processlist, programlist |
+| Extended plugins | folders, amps, ports, raid, wifi, ip |
+| Not ported yet | containers, vms, gpu/npu/mpp, connections, smart, cloud |
+| Python-specific flags | `--trace-malloc`, `--api-doc`, `--api-restful-doc` rejected with a clear error |
+
+## Build and run
+
+```console
+$ cargo build --release
+$ ./target/release/glances                 # terminal UI
+$ ./target/release/glances --stdout-json cpu,mem,load
+$ ./target/release/glances --fetch
+```
+
+## Differential testing
+
+The `tools/parity.py` script compares the Rust implementation with the Python
+reference implementation (the oracle) plugin by plugin: it runs both for a few
+refreshes and diffs the flattened key sets and value types.
+
+```console
+$ python3 -m venv /tmp/opencode/glances-py
+$ /tmp/opencode/glances-py/bin/pip install /path/to/python-glances
+$ cargo build
+$ python3 tools/parity.py            # all implemented plugins
+$ python3 tools/parity.py cpu mem    # selected plugins
+```
+
+## Workspace layout
 
 | Crate | Purpose |
 | --- | --- |
-| `glances-core` | plugin model, config, limits, history, events, filters, output |
-| `glances-plugins` | collectors and plugin registry/engine |
+| `glances-core` | plugin model, config, limits, history, events, filters, processes |
+| `glances-plugins` | collectors, plugin registry and update engine |
 | `glances-tui` | terminal UI (ratatui) |
-| `glances-cli` | the `glances` binary |
+| `glances-cli` | the `glances` binary, stdout modes and fetch renderer |
 
 ## License