target/ast10x0/board: update README with SGPIOM pipeline

target/ast10x0/board/README.md

diff --git a/target/ast10x0/board/README.md b/target/ast10x0/board/README.md
index a606897..1cc7876 100644
--- a/target/ast10x0/board/README.md
+++ b/target/ast10x0/board/README.md
@@ -2,13 +2,49 @@
 
 Board-level integration crate for AST10x0 platforms.
 
-This is the empty scaffold. The crate exists so that board-specific
-descriptors, monitor wiring, and SPIM routing helpers have a stable
-home as they get added on top of the SCU + SPIMONITOR primitives in
-`peripherals`.
+This crate owns board-level hardware initialization and board-selected SGPIOM
+configuration for AST10x0 targets.
+
+## Responsibilities
+
+- Apply board pinctrl groups via SCU
+- Gate/reset board-level peripherals needed at boot (currently I2C flow)
+- Export board descriptor metadata used by runtime init
+- Consume generated SGPIOM configuration selected at board build time
+
+SGPIOM policy is board-owned here, while SGPIOM execution remains in
+`//target/ast10x0/peripherals`.
+
+## SGPIOM JSON Pipeline (Bazel)
+
+The board package wires SGPIOM JSON tooling into Bazel with these targets:
+
+- `//target/ast10x0/board:sgpiom_validate`
+- `//target/ast10x0/board:sgpiom_merged`
+- `//target/ast10x0/board:sgpiom_generate`
+- `//target/ast10x0/board:sgpiom_check`
+- `//target/ast10x0/board:sgpiom_report`
+
+Generated artifact compiled into this crate:
+
+- `sgpiom_config_generated.rs`
+
+See `//tools/sgpiom/README.md` for CLI details and manifest format.
 
 ## Build
 
 ```
 bazelisk build --config=virt_ast10x0 //target/ast10x0/board:ast10x0_board
 ```
+
+For AST1060 hardware config and SGPIOM pipeline artifacts:
+
+```bash
+bazelisk build --config=k_ast1060_evb \
+	//target/ast10x0/board:ast10x0_board \
+	//target/ast10x0/board:sgpiom_validate \
+	//target/ast10x0/board:sgpiom_merged \
+	//target/ast10x0/board:sgpiom_generate \
+	//target/ast10x0/board:sgpiom_check \
+	//target/ast10x0/board:sgpiom_report
+```