fix(inference): tokenize endpoint sent wrong field — every token estimate was 0

LlamaCppTokenizer posted {"tokens":[text]} but llama.cpp's /tokenize expects
{"content":text}; the server silently answered {"tokens":[]}, so countTokens
returned 0 for every string. Every context entry carried tokenEstimate=0 and
the whole budget/trim pipeline was blind — live QA saw a 34k-token prompt
sail through a 16384 stage budget (three raw file_read results of plan docs),
crater t/s, degrade output, and fail the stage on validation 3x.

Also guard estimateTokens: a zero count for non-blank content falls back to
the chars/4 heuristic so a lying tokenizer can never blind budgeting again.

testing/deterministic/src/test/kotlin/DefaultContextPackBuilderTest.kt

@@ -31,6 +31,36 @@ class DefaultContextPackBuilderTest {
         tokenEstimate = tokens
     )
 
+    private fun typedEntry(id: String, layer: ContextLayer, tokens: Int, sourceType: String) = ContextEntry(
+        id = ContextEntryId(id),
+        layer = layer,
+        content = "content-$id",
+        sourceType = sourceType,
+        sourceId = id,
+        tokenEstimate = tokens
+    )
+
+    @Test
+    fun `oversized tool results from a stage tool loop are trimmed to budget`() {
+        // Live repro (2026-06-11): analyst stage with three file_read results of ~5.6k/11.9k/10.7k
+        // tokens sailed through a 16384 budget untrimmed and produced a 34k-token prompt.
+        val entries = listOf(
+            typedEntry("sys", ContextLayer.L0, 3500, "systemPrompt"),
+            typedEntry("task", ContextLayer.L1, 150, "agentPrompt"),
+            typedEntry("call1", ContextLayer.L2, 40, "assistantToolCall"),
+            typedEntry("res1", ContextLayer.L2, 5600, "toolResult"),
+            typedEntry("call2", ContextLayer.L2, 40, "assistantToolCall"),
+            typedEntry("res2", ContextLayer.L2, 11900, "toolResult"),
+            typedEntry("call3", ContextLayer.L2, 40, "assistantToolCall"),
+            typedEntry("res3", ContextLayer.L2, 10700, "toolResult"),
+        )
+        val pack = builder.build(packId, sessionId, stageId, entries, TokenBudget(limit = 16384))
+        assertTrue(
+            pack.budgetUsed <= 16384,
+            "budgetUsed ${pack.budgetUsed} must not exceed the 16384 stage budget",
+        )
+    }
+
     @Test
     fun `build groups entries by layer`() {
         val entries = listOf(