feat(ai): AI Data Access grants live on the node, not in localStorage

Operator: "the AI Data Access settings are not persistent through sessions,
often turns them all off."

They were stored in localStorage, which is scoped to an ORIGIN — and a node
answers on several: LAN address, Tailscale address, <host>.local, hostname.
Granting Media over the LAN and returning over Tailscale showed every switch
off again. Not reset: never set *there*. It also made a working content path
look broken, because every scope silently returns nothing without a grant, so
an ungranted permission is indistinguishable from an empty library — that is
exactly what an empty films search turned out to be.

The grant answers "what may the assistant read about THIS NODE", which is a
property of the node, not of one browser at one address. New
settings/ai_permissions.rs (same shape as session_policy: atomic temp+rename,
sanitised on read and write, fails closed on a corrupt file — an unreadable
grant file must never read as "everything allowed"). New ai.permissions.get /
.set, absent from the unauthenticated allowlist so they require a session.

Migration, not replacement: if this browser holds grants and the node holds
none, the local set is pushed UP rather than wiped. Without that, upgrading
would silently revoke the grants of everyone who set them before this change.
The node still wins in every other direction, so a revocation made on one
device takes effect everywhere — otherwise revoking would be impossible from a
second device.

Unknown category ids are stored verbatim rather than validated against a
hardcoded list: a third copy of that list would silently drop a new category on
upgrade. Storing a category grants nothing by itself — the broker checks before
fetching and the node re-checks before answering (T-13-33).

Hydration happens ONCE at broker start, not inside each permission gate: the
gates are hot-path, and awaiting there adds an RPC to every content and context
request. The first attempt did it per-gate and the existing broker tests caught
it by failing on consumed mocks.

Rust 7/7, store 18/18, broker 23/23.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

core/archipelago/src/api/rpc/dispatcher.rs

@@ -491,6 +491,8 @@ impl RpcHandler {
             "system.factory-reset" => self.handle_system_factory_reset(params).await,
             "auth.session-policy.get" => self.handle_session_policy_get().await,
             "auth.session-policy.set" => self.handle_session_policy_set(params).await,
+            "ai.permissions.get" => self.handle_ai_permissions_get().await,
+            "ai.permissions.set" => self.handle_ai_permissions_set(params).await,
             "system.settings.get" => self.handle_system_settings_get(params).await,
             "system.settings.set" => self.handle_system_settings_set(params).await,
             "system.kiosk-display.get" => self.handle_system_kiosk_display_get().await,

core/archipelago/src/api/rpc/system/handlers.rs

@@ -1011,6 +1011,48 @@ impl RpcHandler {
         }
     }
 
+    /// ai.permissions.get — what the assistant may read about this node.
+    ///
+    /// Node-side because these grants were in per-origin localStorage, so they
+    /// vanished whenever the operator reached the node by a different address.
+    pub(in crate::api::rpc) async fn handle_ai_permissions_get(
+        &self,
+    ) -> Result<serde_json::Value> {
+        let perms = crate::settings::ai_permissions::load(&self.config.data_dir).await;
+        Ok(serde_json::json!({ "granted": perms.granted }))
+    }
+
+    /// ai.permissions.set — replace the grant set.
+    ///
+    /// Whole-set replacement rather than per-category toggles: the UI owns a
+    /// checkbox list and always knows the complete desired state, and a
+    /// toggle API would race itself when two tabs are open. The stored value
+    /// is echoed back so the caller sees exactly what was kept after
+    /// sanitising, which makes a dropped malformed entry visible instead of
+    /// silent.
+    pub(in crate::api::rpc) async fn handle_ai_permissions_set(
+        &self,
+        params: Option<serde_json::Value>,
+    ) -> Result<serde_json::Value> {
+        let params = params.unwrap_or(serde_json::json!({}));
+        let granted: Vec<String> = params
+            .get("granted")
+            .and_then(|v| v.as_array())
+            .map(|a| {
+                a.iter()
+                    .filter_map(|v| v.as_str().map(str::to_string))
+                    .collect()
+            })
+            .ok_or_else(|| anyhow::anyhow!("Missing granted (array of category ids)"))?;
+
+        let saved = crate::settings::ai_permissions::save(
+            &self.config.data_dir,
+            crate::settings::ai_permissions::AiPermissions { granted },
+        )
+        .await?;
+        Ok(serde_json::json!({ "granted": saved.granted }))
+    }
+
     /// auth.session-policy.get — how long a login lasts on this node.
     pub(in crate::api::rpc) async fn handle_session_policy_get(&self) -> Result<serde_json::Value> {
         let policy = crate::settings::session_policy::load(&self.config.data_dir).await;

core/archipelago/src/settings/ai_permissions.rs

@@ -0,0 +1,184 @@
+//! What the assistant is allowed to read about this node.
+//!
+//! # Why this lives on the node and not in the browser
+//!
+//! These grants were stored in `localStorage`, which is scoped to an
+//! **origin**. A node answers on several: its LAN address, its Tailscale
+//! address, `<host>.local`, and its hostname. Granting "Media" over the LAN
+//! and returning over Tailscale showed every switch off again — not reset,
+//! simply never set *there*. Operator-reported as "the AI Data Access settings
+//! are not persistent through sessions, often turns them all off", and it made
+//! a working content path look broken: every scope silently returns nothing
+//! without a grant, so an ungranted permission is indistinguishable from an
+//! empty library.
+//!
+//! The grant answers "what may the assistant read **about this node**". That is
+//! a property of the node, not of one browser at one address, so the node is
+//! where it belongs. Stored here it survives a cache clear, a new device, a
+//! different browser, and any change of address.
+//!
+//! # Why the category list is not validated against a hardcoded set
+//!
+//! The authoritative list of categories lives in the UI
+//! (`AI_PERMISSION_CATEGORIES`) and in the context broker's `fetchAndSanitize`.
+//! Duplicating it here would create a third copy that silently drops a new
+//! category on upgrade — the grant would round-trip through an older node and
+//! come back missing. Unknown strings are stored verbatim and simply never
+//! match a fetch, which fails closed. **Storing a category grants nothing on
+//! its own**: the broker checks each category before it fetches, and the node
+//! re-checks before it answers (T-13-33). This file records intent; it is not
+//! the enforcement point.
+
+use serde::{Deserialize, Serialize};
+use std::path::Path;
+
+const FILE_PATH: &str = "settings/ai_permissions.json";
+
+/// Defence against a hand-edited or hostile file turning into unbounded
+/// memory. Far above any real category count.
+const MAX_CATEGORIES: usize = 64;
+const MAX_CATEGORY_LEN: usize = 64;
+
+#[derive(Debug, Clone, Default, PartialEq, Eq, Serialize, Deserialize)]
+pub struct AiPermissions {
+    /// Categories the operator has granted. Empty means the assistant reads
+    /// nothing about this node, which is the default: a fresh node grants
+    /// nothing until asked.
+    #[serde(default)]
+    pub granted: Vec<String>,
+}
+
+impl AiPermissions {
+    /// Drop anything malformed and de-duplicate. Applied on both read and
+    /// write so a hand-edited file cannot produce a state the UI can never
+    /// display or undo.
+    pub fn sanitized(mut self) -> Self {
+        self.granted.retain(|c| {
+            !c.is_empty()
+                && c.len() <= MAX_CATEGORY_LEN
+                // Category ids are lowercase kebab (`ai-local`). Anything else
+                // is not something this node will ever match against.
+                && c.chars()
+                    .all(|ch| ch.is_ascii_lowercase() || ch.is_ascii_digit() || ch == '-')
+        });
+        self.granted.sort();
+        self.granted.dedup();
+        self.granted.truncate(MAX_CATEGORIES);
+        self
+    }
+
+    pub fn is_granted(&self, category: &str) -> bool {
+        self.granted.iter().any(|c| c == category)
+    }
+}
+
+pub async fn load(data_dir: &Path) -> AiPermissions {
+    let path = data_dir.join(FILE_PATH);
+    match tokio::fs::read(&path).await {
+        Ok(bytes) => serde_json::from_slice::<AiPermissions>(&bytes)
+            .map(AiPermissions::sanitized)
+            .unwrap_or_else(|e| {
+                // Fail closed. An unreadable grant file must not be treated as
+                // "everything allowed" — the assistant simply reads nothing
+                // until the operator sets it again.
+                tracing::warn!(error = %e, "AI permissions unreadable; granting nothing");
+                AiPermissions::default()
+            }),
+        // Absent file is the ordinary first-run case, not an error.
+        Err(_) => AiPermissions::default(),
+    }
+}
+
+pub async fn save(data_dir: &Path, perms: AiPermissions) -> anyhow::Result<AiPermissions> {
+    let perms = perms.sanitized();
+    let path = data_dir.join(FILE_PATH);
+    if let Some(parent) = path.parent() {
+        tokio::fs::create_dir_all(parent).await?;
+    }
+    // Temp + rename so a crash mid-write cannot leave a truncated file that
+    // reads as "no grants" on the next boot.
+    let tmp = path.with_extension("json.tmp");
+    tokio::fs::write(&tmp, serde_json::to_vec_pretty(&perms)?).await?;
+    tokio::fs::rename(&tmp, &path).await?;
+    Ok(perms)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn a_fresh_node_grants_nothing() {
+        assert!(AiPermissions::default().granted.is_empty());
+        assert!(!AiPermissions::default().is_granted("media"));
+    }
+
+    #[test]
+    fn unknown_categories_survive_a_round_trip() {
+        // A newer UI may grant a category this binary has never heard of.
+        // Dropping it would silently revoke the grant on downgrade/upgrade.
+        let p = AiPermissions {
+            granted: vec!["media".into(), "some-future-category".into()],
+        }
+        .sanitized();
+        assert!(p.is_granted("some-future-category"));
+    }
+
+    #[test]
+    fn malformed_entries_are_dropped_not_stored() {
+        let p = AiPermissions {
+            granted: vec![
+                "media".into(),
+                "".into(),
+                "UPPER".into(),
+                "has space".into(),
+                "../../etc/passwd".into(),
+                "x".repeat(500),
+            ],
+        }
+        .sanitized();
+        assert_eq!(p.granted, vec!["media".to_string()]);
+    }
+
+    #[test]
+    fn duplicates_collapse() {
+        let p = AiPermissions {
+            granted: vec!["media".into(), "media".into(), "files".into()],
+        }
+        .sanitized();
+        assert_eq!(p.granted, vec!["files".to_string(), "media".to_string()]);
+    }
+
+    #[tokio::test]
+    async fn absent_file_reads_as_no_grants_rather_than_an_error() {
+        let dir = tempfile::tempdir().unwrap();
+        assert!(load(dir.path()).await.granted.is_empty());
+    }
+
+    #[tokio::test]
+    async fn a_corrupt_file_fails_closed() {
+        let dir = tempfile::tempdir().unwrap();
+        let path = dir.path().join(FILE_PATH);
+        tokio::fs::create_dir_all(path.parent().unwrap()).await.unwrap();
+        tokio::fs::write(&path, b"{ not json").await.unwrap();
+        // The dangerous failure would be defaulting to "all granted".
+        assert!(load(dir.path()).await.granted.is_empty());
+    }
+
+    #[tokio::test]
+    async fn saved_grants_survive_a_reload() {
+        let dir = tempfile::tempdir().unwrap();
+        save(
+            dir.path(),
+            AiPermissions {
+                granted: vec!["media".into(), "files".into()],
+            },
+        )
+        .await
+        .unwrap();
+        let back = load(dir.path()).await;
+        assert!(back.is_granted("media"));
+        assert!(back.is_granted("files"));
+        assert!(!back.is_granted("wallet"));
+    }
+}

core/archipelago/src/settings/mod.rs

@@ -4,5 +4,6 @@
 //! call sites (deep in the transport / RPC / ingest stacks) don't need
 //! to thread a data_dir or Arc through the entire call graph.
 
+pub mod ai_permissions;
 pub mod session_policy;
 pub mod transport;