fix(ah-staking): stall detection grace period, MinerPages fix, and simulation tools

- Add 3-session grace period to stall detection to allow RC XCM round-trip
  before triggering era recovery (StallDetectionCount storage added)
- Fix plan_new_era() to always increment CurrentEra regardless of
  ElectionProvider::start() result, preventing infinite retry loops
- Fix MinerPages from 2 to 32 to match Pages config (was causing
  incomplete OCW solutions and election failures)
- Bump AH spec_version to 1_020_007
- Add subxt example scripts for simulation and mainnet operations
- Remove obsolete fix_force_era.rs (replaced by sim_reset_election.rs)

vendor/pezkuwi-subxt/subxt/examples/set_ah_client_active.rs

@@ -0,0 +1,94 @@
+//! Set StakingAhClient mode to Active on RC
+//!
+//! Run:
+//!   SUDO_MNEMONIC="..." cargo run --release -p pezkuwi-subxt --example set_ah_client_active
+
+#![allow(missing_docs)]
+use pezkuwi_subxt::dynamic::Value;
+use pezkuwi_subxt::{OnlineClient, PezkuwiConfig};
+use pezkuwi_subxt_signer::bip39::Mnemonic;
+use pezkuwi_subxt_signer::sr25519::Keypair;
+use std::str::FromStr;
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+	println!("=== SET StakingAhClient MODE → Active ===\n");
+
+	let rc_url =
+		std::env::var("RC_RPC").unwrap_or_else(|_| "ws://127.0.0.1:9944".to_string());
+	let api = OnlineClient::<PezkuwiConfig>::from_url(&rc_url).await?;
+	println!("RC connected: spec {}", api.runtime_version().spec_version);
+
+	let mnemonic_str =
+		std::env::var("SUDO_MNEMONIC").expect("SUDO_MNEMONIC environment variable required");
+	let mnemonic = Mnemonic::from_str(&mnemonic_str)?;
+	let sudo_keypair = Keypair::from_phrase(&mnemonic, None)?;
+	println!("Sudo: {}\n", sudo_keypair.public_key().to_account_id());
+
+	// Check current mode first
+	let mode_key = pezsp_crypto_hashing::twox_128(b"StakingAhClient")
+		.iter()
+		.chain(pezsp_crypto_hashing::twox_128(b"Mode").iter())
+		.copied()
+		.collect::<Vec<u8>>();
+	let mode_val = match api.storage().at_latest().await?.fetch_raw(mode_key.clone()).await {
+		Ok(data) => data,
+		Err(_) => vec![],
+	};
+	let current_mode = if mode_val.is_empty() {
+		"Passive (default/not set)"
+	} else {
+		match mode_val[0] {
+			0 => "Passive",
+			1 => "Buffered",
+			2 => "Active",
+			_ => "Unknown",
+		}
+	};
+	println!("Current mode: {}", current_mode);
+
+	// StakingAhClient.set_mode(Active)
+	let set_mode = pezkuwi_subxt::dynamic::tx(
+		"StakingAhClient",
+		"set_mode",
+		vec![Value::unnamed_variant("Active", vec![])],
+	);
+	let sudo_tx =
+		pezkuwi_subxt::dynamic::tx("Sudo", "sudo", vec![set_mode.into_value()]);
+
+	println!("Submitting sudo(StakingAhClient.set_mode(Active))...");
+	let progress = api
+		.tx()
+		.sign_and_submit_then_watch_default(&sudo_tx, &sudo_keypair)
+		.await?;
+	let events = progress.wait_for_finalized_success().await?;
+
+	for event in events.iter() {
+		let event = event?;
+		println!("  {}::{}", event.pallet_name(), event.variant_name());
+	}
+
+	// Verify new mode
+	let mode_val = match api.storage().at_latest().await?.fetch_raw(mode_key.clone()).await {
+		Ok(data) => data,
+		Err(_) => vec![],
+	};
+	let new_mode = if mode_val.is_empty() {
+		"(not found)"
+	} else {
+		match mode_val[0] {
+			0 => "Passive",
+			1 => "Buffered",
+			2 => "Active",
+			_ => "Unknown",
+		}
+	};
+	println!("\nNew mode: {}", new_mode);
+
+	if new_mode == "Active" {
+		println!("\nStakingAhClient is now Active!");
+		println!("RC will send SessionReports to AH via XCM at each session end.");
+	}
+
+	Ok(())
+}