u/complete: persistent copilot session per cwd; add freeloader hook

- Replace per-invocation s/bfg calls with a persistent *-copilot session
  looked up from s/idx; first call in a cwd spawns the session, subsequent
  calls reuse it, skipping s/new overhead
- Clear context after each completion so inference stays fast
- Fix session lookup to read s/idx instead of globbing the 9P mount
- Add x/freeloader turnError hook to copilot.json

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

agents/copilot.json

@@ -1,4 +1,9 @@
 {
   "prompt": [],
-  "trustedTools": []
+  "trustedTools": [],
+  "hooks": {
+    "turnError": [
+      "$OLLIE/x/freeloader $OLLIE_SESSION_ID"
+    ]
+  }
 }

scripts/u/complete

@@ -6,7 +6,6 @@ PREFIX_MAX=4000
 SUFFIX_MAX=1000
 
 MOUNT=${OLLIE:-$HOME/mnt/ollie}
-BFG="${0%/*}/../s/bfg"
 
 cmd=${0##*/}
 die() { printf '%s: %s\n' "$cmd" "$*" >&2; exit 1; }
@@ -42,6 +41,41 @@ done
 
 [ -z "${winid:-}" ] || [ "$winid" = "0" ] && die "must be run from an acme window"
 
+# Find or create a copilot session for the current working directory.
+# Reuses an existing *-copilot session in this cwd if one is alive,
+# otherwise spawns a new one.
+find_or_create_session() {
+    local target_cwd="$1"
+    local sdir state scwd id kv deadline
+
+    while IFS= read -r line; do
+        id=${line%%$'\t'*}
+        case "$id" in *-copilot) ;; *) continue ;; esac
+        sdir="$MOUNT/s/$id"
+        [ -d "$sdir" ] || continue
+        scwd=$(cat "$sdir/cwd" 2>/dev/null) || continue
+        [ "$scwd" = "$target_cwd" ] || continue
+        state=$(cat "$sdir/state" 2>/dev/null) || continue
+        case "$state" in failed*|error*) continue ;; esac
+        printf '%s\n' "$id"
+        return 0
+    done < "$MOUNT/s/idx"
+
+    id="$(date +%s%N)-copilot"
+    kv="name=${id}
+cwd=${target_cwd}
+agent=copilot
+backend=${backend}
+model=${model}"
+    printf '%s\n' "$kv" > "$MOUNT/s/new" || die "failed to create copilot session"
+
+    deadline=$(( $(date +%s) + 5 ))
+    until [ -d "$MOUNT/s/$id" ] || [ "$(date +%s)" -ge "$deadline" ]; do sleep 0.05; done
+    [ -d "$MOUNT/s/$id" ] || die "timeout waiting for copilot session"
+
+    printf '%s\n' "$id"
+}
+
 # Get filename for language context (last field of ctl line 1)
 filename=$(9p read acme/$winid/ctl | awk 'NR==1{print $NF}')
 
@@ -62,16 +96,29 @@ suffix=$(9p read acme/$winid/data)
 prefix="${prefix: -$PREFIX_MAX}"
 suffix="${suffix:0:$SUFFIX_MAX}"
 
-# Query model
-result=$("$BFG" -agent copilot -model "$model" -backend "$backend" \
-    "Complete the code at the cursor in ${filename}. Output ONLY the text to insert — no explanation, no markdown, no preamble.
+# Find or create the copilot session, then submit
+sid=$(find_or_create_session "$PWD")
+B="$MOUNT/s/$sid"
+
+printf '%s\n' "Complete the code at the cursor in ${filename}. Output ONLY the text to insert — no explanation, no markdown, no preamble.
 
 <prefix>
 ${prefix}
 </prefix>
 <suffix>
 ${suffix}
-</suffix>")
+</suffix>" > "$B/prompt"
+
+# Wait for idle
+while true; do
+    state=$(cat "$B/statewait" 2>/dev/null | tr -d '[:space:]') || break
+    [ "$state" = "idle" ] && break
+done
+
+# Read result from offset, then clear context for next completion
+offset=$(cat "$B/offset" 2>/dev/null || echo 0)
+result=$(tail -c +$((offset + 1)) "$B/chat" 2>/dev/null)
+echo "clear" > "$B/ctl"
 
 # Write completion to a new acme window
 newid=$(9p read acme/new/ctl | awk 'NR==1{print $1}')