Auto: ablegacy-7 — array contiguous block addressing

Closes #250

docs/Driver.AbLegacy.Cli.md

@@ -95,6 +95,37 @@ PLC-managed — use with caution.
 otopcua-ablegacy-cli subscribe -g ab://192.168.1.20/1,0 -a N7:10 -t Int -i 500
 ```
 
+## Array reads
+
+PR 7 — one PCCC frame can carry up to ~120 words. Address an array tag with either the
+Rockwell-native `,N` suffix or the libplctag-native `[N]` suffix on the word number; both
+forms canonicalise to `[N]` when the driver hands the tag to libplctag, and the parser
+caps `N` at 120.
+
+```powershell
+# Rockwell `,N` form — "10 consecutive words starting at N7:0"
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a "N7:0,10" -t Int
+
+# libplctag `[N]` form — same wire result
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a "N7:0[10]" -t Int
+
+# Float / Long arrays — same suffix syntax, narrower frame ceiling on Float (~60 elements)
+# and Long (~60 elements) because each element is 4 bytes vs Int's 2.
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a "F8:0,4" -t Float
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a "L19:0,4" -t Long
+
+# --array-length override — pin the element count from config rather than the address
+# suffix. Wins over the parsed `,N` / `[N]` value when both are set; useful for keeping the
+# address string compact while bumping the element count from a tags config file.
+otopcua-ablegacy-cli read -g ab://192.168.1.20/1,0 -a "N7:0" --array-length 10 -t Int
+```
+
+Array tags reject sub-element references (`T4:0,5.ACC`) and bit suffixes (`N7:0,10/3`) at
+parse time — both combinations are semantically meaningless against a contiguous block.
+
+For `B`-files the Rockwell convention is "one BOOL per word, not per bit": `B3:0,10`
+returns `bool[10]` (one per word's non-zero state), not `bool[160]`.
+
 ## Known caveat — ab_server upstream gap
 
 The integration-fixture `ab_server` Docker container accepts TCP but its PCCC

docs/drivers/AbLegacy-Test-Fixture.md

@@ -36,6 +36,12 @@ supplies a `FakeAbLegacyTag`.
 
 - `AbLegacyAddressTests` — PCCC address parsing for SLC / MicroLogix / PLC-5
   / LogixPccc-mode (`N7:0`, `F8:12`, `B3:0/5`, etc.)
+- `AbLegacyArrayTests` — PR 7 array contiguous-block addressing: parser
+  positives + rejects for `,N` / `[N]` suffixes, options-override
+  (`ArrayLength`), driver `IsArray` discovery, and array decoding for N / F /
+  L / B files (Rockwell convention: one BOOL per word for `B3:0,10`). Latency
+  benchmark against the Docker fixture is a perf-flagged integration case in
+  `AbLegacyArrayReadTests` — runs only when ab_server is reachable.
 - `AbLegacyCapabilityTests` — data type mapping, read-only enforcement
 - `AbLegacyReadWriteTests` — read + write happy + error paths against the fake
 - `AbLegacyBitRmwTests` — bit-within-DINT read-modify-write serialization via