fix(honcho): read Honcho 3.0.x response schema — memory reads were silently empty

Against a self-hosted Honcho 3.0.11 every read path came back empty while
the server was healthy and full of derived facts: the plugin parsed a
`conclusions`/`summary` shape the API no longer emits.

- honcho-client: typed models for the real schema — `PeerContext`
  (`representation` markdown + `peer_card`), `SessionContext` (`summary` as
  an object, `peer_representation`), wrapped `PeerCard` (a bare array on PUT
  is a 422, which also broke `honcho_profile` writes).
- plugin: the turn-time injection and `honcho_context` read the
  representation; `honcho_search` and the page's /search now use
  `conclusions/query` (observer/observed scoping inside `filters`) — a real
  ranked semantic search with fact ids, which `peer_context?search_query`
  never provided; /overview returns card + representation + conclusions.
- compose: pin the Honcho image by digest (3.0.11) — ghcr publishes no v3
  semver tags, and an untracked `:latest` pull is what drifted the schema.
- tests: fixture tests from payloads captured on the live server, plus an
  env-gated live smoke test (HONCHO_E2E_URL/_WS/_PEER, `cargo test
  -p honcho-client -- --ignored`) — run it before any future Honcho bump.

crates/honcho-client/src/sessions.rs

@@ -161,14 +161,17 @@ impl HonchoClient {
 
     // ── Context / Summaries ───────────────────────────────────────────────
 
-    /// Retrieve context for a session (messages + peer conclusions, token-budgeted).
+    /// Retrieve context for a session (messages + summary + the session peer's
+    /// representation, token-budgeted). The summary is a `Summary` object and
+    /// the facts live in `peer_representation` — there is no `conclusions`
+    /// array (see [`SessionContext`]).
     pub async fn session_context(
         &self,
         workspace_id: &str,
         session_id: &str,
         tokens: Option<u32>,
         search_query: Option<&str>,
-    ) -> Result<serde_json::Value> {
+    ) -> Result<SessionContext> {
         let mut q: Vec<(&str, String)> = vec![];
         if let Some(t) = tokens {
             q.push(("tokens", t.to_string()));