Fix and enrich statusline context-token display

The brace-bounded grep truncated at the first nested "}" in the usage
object, so the token segment silently rendered empty. Parse each
transcript JSONL line as JSON instead, summing input + cache_read +
cache_creation to match /context's window-occupancy figure.

Show it as "X.Xk/<limit> tokens (Y%)" with the limit auto-sized to the
model's context window (1m vs 200k), and color the segment red once
context reaches 200k.

adapters/claude/statusline.sh

@@ -18,28 +18,37 @@ if command -v git >/dev/null 2>&1; then
   [ "$branch" = "HEAD" ] && branch=$(git -C "${cwd/#\~/$HOME}" rev-parse --short HEAD 2>/dev/null)
 fi
 
-# 3. Model display name
+# 3. Model display name and id (id used to size the context window below)
 model=$(printf '%s' "$input" | jq -r '.model.display_name // empty' 2>/dev/null)
+model_id=$(printf '%s' "$input" | jq -r '.model.id // .model.display_name // empty' 2>/dev/null)
 
-# 4. Token count from transcript JSONL
+# 4. Context-window occupancy from transcript JSONL.
+#    Matches /context: input + cache_read + cache_creation of the most recent
+#    request is exactly what currently occupies the context window. The usage
+#    object nests sub-objects, so parse each JSONL line as JSON rather than
+#    grepping (a brace-bounded grep truncates at the first nested "}").
 ctx=""
 transcript=$(printf '%s' "$input" | jq -r '.transcript_path // empty' 2>/dev/null)
 if [ -n "$transcript" ] && [ -r "$transcript" ] && command -v jq >/dev/null 2>&1; then
-  raw=$(grep -o '"usage":{[^}]*}' "$transcript" 2>/dev/null | tail -1)
-  if [ -n "$raw" ]; then
-    total=$(printf '%s' "{$raw}" | jq -r '
-      .usage |
-      ((.input_tokens // 0)
-       + (.cache_read_input_tokens // 0)
-       + (.cache_creation_input_tokens // 0)
-       + (.output_tokens // 0))
-    ' 2>/dev/null)
-    if [ -n "$total" ] && [ "$total" -gt 0 ] 2>/dev/null; then
-      if [ "$total" -ge 1000 ]; then
-        ctx=$(awk "BEGIN { printf \"%.1fk ctx\", $total/1000 }")
-      else
-        ctx="${total} ctx"
-      fi
+  total=$(tail -n 300 "$transcript" 2>/dev/null | jq -rR '
+    fromjson? | (.message.usage // .usage) // empty
+    | select(.input_tokens != null)
+    | (.input_tokens + (.cache_read_input_tokens // 0) + (.cache_creation_input_tokens // 0))
+  ' 2>/dev/null | tail -1)
+  if [ -n "$total" ] && [ "$total" -gt 0 ] 2>/dev/null; then
+    # 1M-context models report a [1m]/"1M" marker in the id/name; else 200k.
+    case "$model_id" in
+      *1m*|*1M*) limit=1000000; label="1m" ;;
+      *)         limit=200000;  label="200k" ;;
+    esac
+    ctx=$(awk -v t="$total" -v lim="$limit" -v lab="$label" 'BEGIN {
+      if (t >= 1000) ts = sprintf("%.1fk", t/1000); else ts = sprintf("%d", t);
+      printf "%s/%s tokens (%.0f%%)", ts, lab, t*100/lim
+    }')
+    # Turn the token segment red once context reaches 200k; reset after so the
+    # rest of the line keeps its default styling.
+    if [ "$total" -ge 200000 ] 2>/dev/null; then
+      ctx=$(printf '\033[31m%s\033[0m' "$ctx")
     fi
   fi
 fi