feat(cli): add pm3py client — autocompleting console over the stock proxmark3 client

Wraps the standard Proxmark3 C client (so it works with any Proxmark/firmware) in a prompt_toolkit REPL: full command-tree completion sourced from the client's commands.json, option-flag completion, Tab-to-descend, a press-right help toggle, and the client's own coloured output.

Two swappable backends behind ClientDriver: in-process SWIG (_pm3) by default, a pexpect-around-the-binary fallback otherwise. Both auto-detect /dev/ttyACM* and discover the checkout via its doc/commands.json marker (walk-up + side-by-side), so no path is hardcoded.

`pm3py client --pack OUT` spins off a self-contained drop-in — a readable .py, or a .pyz with prompt_toolkit/pexpect bundled — amalgamated from the package (the tested source of truth) so it can't drift. Adds pexpect to deps; hardware-free tests in tests/test_clientcli.py.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/fixtures/commands_min.json

@@ -0,0 +1,55 @@
+{
+  "metadata": {
+    "commands_extracted": 5,
+    "extracted_by": "test-fixture",
+    "extracted_on": "2026-01-01T00:00:00+00:00"
+  },
+  "commands": {
+    "clear": {
+      "command": "clear",
+      "description": "Clear screen",
+      "notes": [],
+      "offline": true,
+      "options": ["-h, --help This help"],
+      "usage": "clear [-h]"
+    },
+    "hf 14a info": {
+      "command": "hf 14a info",
+      "description": "Get info about an ISO14443-A tag",
+      "notes": ["hf 14a info -v"],
+      "offline": false,
+      "options": ["-h, --help This help", "-v, --verbose verbose output"],
+      "usage": "hf 14a info [-hv]"
+    },
+    "hf mf rdbl": {
+      "command": "hf mf rdbl",
+      "description": "Read MIFARE Classic block",
+      "notes": ["hf mf rdbl --blk 0", "hf mf rdbl --blk 0 -k A0A1A2A3A4A5"],
+      "offline": false,
+      "options": [
+        "-h, --help This help",
+        "--blk <dec> block number",
+        "-a input key type is key A (def)",
+        "-k, --key <hex> key, 6 hex bytes",
+        "-v, --verbose verbose output"
+      ],
+      "usage": "hf mf rdbl [-habv] --blk <dec> [-k <hex>]"
+    },
+    "hf mf wrbl": {
+      "command": "hf mf wrbl",
+      "description": "Write MIFARE Classic block",
+      "notes": [],
+      "offline": false,
+      "options": ["-h, --help This help", "--blk <dec> block number", "-k, --key <hex> key, 6 hex bytes"],
+      "usage": "hf mf wrbl [-h] --blk <dec> [-k <hex>]"
+    },
+    "lf search": {
+      "command": "lf search",
+      "description": "Read and identify a LF tag",
+      "notes": ["lf search -1"],
+      "offline": false,
+      "options": ["-h, --help This help", "-1 Use data from Graphbuffer (offline mode)", "-c Continue searching"],
+      "usage": "lf search [-1ch]"
+    }
+  }
+}