fix(ablegacy): review fixes - one family-aware address authority in Contracts, deploy gate + editor check, malformed address -> BadNodeIdUnknown warned once, probe normalised, octal/migration docs (#244 #245 #247)

Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe

docs/drivers/AbLegacy.md

@@ -97,9 +97,21 @@ physical inputs and may reject the write.
   bit 7 and `I:017/17` is bit 15. Only `I`/`O` on PLC-5 (`OctalIoAddressing` on the family profile) — SLC,
   MicroLogix and Logix-PCCC stay decimal, and PLC-5 `N`/`B`/... files stay decimal. The record stores decimal and
   `ToLibplctagName()` **emits decimal**, so the libplctag `name=` string and the string the native transport
-  re-parses carry identical numbers. ⚠️ *Unverified:* whether libplctag itself reads PLC-5 I/O indices as octal
-  when handed the raw RSLogix text was not checked (no libplctag source/PLC here); the driver therefore never
-  hands it octal text. Native PLC-5 is N-file read-only anyway, so I/O never reaches the native wire.
+  re-parses carry identical numbers. This is not a double conversion: libplctag's `pccc.c`
+  (`parse_pccc_elem_num` / `parse_pccc_bit_num`) parses decimal numerals only (a FIXME there says octal is
+  unsupported), so the driver must convert. Pinned by `Plc5_io_indices_are_octal` (`I:017/17` -> `I:15/15`).
+  The connectivity-probe address is normalised the same way.
+  - ⚠️ **Behaviour change / migration.** Before this change a PLC-5 `I:`/`O:` address was passed to libplctag as
+    written, i.e. read as **decimal**. An address copied from RSLogix in octal (e.g. `I:017`) therefore read the
+    wrong word, and an authored decimal such as `I:1/12` now means bit 10 (octal 12). A previously "working"
+    address containing the digits 8 or 9 (`I:018`, `O:1/9`) is no longer valid on PLC-5. Re-author any PLC-5
+    I/O tags in RSLogix octal. Such a tag is refused (see below), never silently misread.
+  - **A malformed / family-invalid address** (also: a function-file letter off MicroLogix) reads and writes
+    `BadNodeIdUnknown` for that tag only, creates no runtime, leaves driver health alone, and logs **one**
+    Warning per tag. The same check (`AbLegacyAddress.Validate`) runs in the AdminUI tag editor (family-independent:
+    rejects only what *no* family accepts) and the deploy gate (`EquipmentTagConfigInspector`, using the device's
+    `DeviceConfig.PlcFamily`, absent = SLC 500, unrecognised = unknown) — so `I:018` on a PLC-5 device warns at
+    deploy (an error under `TagConfigValidationMode.Error`), and the editor is never stricter than the gate.
 - **MicroLogix function files (#245).** `RTC`, `HSC`, `DLS`, `MMI`, `PTO`, `PWM`, `STI`, `EII`, `IOS`, `BHI`
   (single fixed instance — no file number — with a `.SUBELEMENT`; no bit index) parse on MicroLogix devices only.
   `AbLegacyFunctionFile.SubElementType` carries the sub-element catalogue (flags → Boolean, words → Int32; unknown