feat(simulation): voice pipeline integration — Factual bypass, observer wiring, tell iteration (#650 #652 #651)

ContentType::Factual bypasses LLM for fact-bearing lines (numbers,
denials). Observer enrichment systems rewrite dialogue/conversation
text with voiced versions before snapshot assembly. Friendly and
RoutineDeviation tells get concrete surface-pattern examples.

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

server/src/voice/prompt_builder.rs

@@ -22,6 +22,13 @@ pub enum ContentType {
     Dialogue,
     /// Observable behavior description — re-voiced with "Describe".
     Behavior,
+    /// Fact-bearing line — numbers, causal chains, denials.
+    ///
+    /// Factual lines bypass the LLM entirely and are served as base text.
+    /// Spike 2 showed 2B models corrupt quantitative content ("14 crates in
+    /// bay seven" → "fourteen crates are missing") and invert denials.
+    /// The simulation is the truth layer — the LLM only handles register.
+    Factual,
 }
 
 /// Result of prompt building, including which injections fired.
@@ -57,6 +64,15 @@ OUTPUT CONSTRAINTS:\n\
 /// "make sentences shorter" instruction causes destructive compression that
 /// strips facts. Long-Angry instead preserves the full claim and focuses
 /// intensity on one sentence.
+///
+/// ## Iteration history for Friendly and RoutineDeviation
+///
+/// Spike 2 showed these two tells produce output indistinguishable from neutral
+/// on Gemma 2B. Tracked against a 3-iteration budget (#651):
+///
+/// - **Iteration 1** (Sprint 26): Replaced abstract instructions with concrete
+///   surface-pattern examples. Friendly: closing aside pattern. RoutineDeviation:
+///   self-correction/echo pattern. Both more imitable for a 2B model.
 fn tell_injector(category: TellCategory) -> &'static str {
     match category {
         TellCategory::Nervous => {
@@ -70,9 +86,12 @@ fn tell_injector(category: TellCategory) -> &'static str {
              Do not say they seem angry."
         }
         TellCategory::Friendly => {
-            "TONE: Add one small extra detail or aside that wasn't strictly necessary. \
-             Example: \"Inspection's tomorrow — should be fine, though.\" \
-             Do not add compliments or forced warmth."
+            // Iteration 1: replaced abstract "add detail" with a concrete closing-aside
+            // pattern. 2B models need a recognisable syntactic target, not a description
+            // of intent. "actually" / "so that's something" are learnable short tokens.
+            "TONE: End with a brief unprompted aside — a phrase the person didn't need to say. \
+             Example: \"Parts are in, so that's something.\" or \"Shift's been quiet, actually.\" \
+             Do not use praise or warm adjectives. One short beat after the main point."
         }
         TellCategory::Guarded => {
             "TONE: Use formal, precise words. Answer exactly what was asked, nothing extra. \
@@ -80,9 +99,12 @@ fn tell_injector(category: TellCategory) -> &'static str {
              Do not say they seem guarded."
         }
         TellCategory::RoutineDeviation => {
-            "TONE: Start the sentence on topic, then add a brief unfinished thought about something else. \
-             Example: \"Pressure's fine. I was going to — anyway, it's logged.\" \
-             Do not explain what they were thinking about."
+            // Iteration 1: replaced the two-step interrupted-thought pattern (too complex
+            // for 2B) with a simpler self-correction / word-echo pattern. The model only
+            // needs to repeat a key word or phrase — one concrete surface action.
+            "TONE: Repeat a key word or phrase, as if catching mid-thought. \
+             Example: \"Logged it. Got it logged, yeah.\" or \"Pressure's — pressure's holding.\" \
+             Do not explain. Just the echo."
         }
     }
 }
@@ -269,6 +291,11 @@ pub fn build_prompt(
             "Describe the following action as a third-person observer. \
              Preserve all individual actions in sequence. Do not extract conclusions"
         }
+        ContentType::Factual => {
+            // Factual lines must be intercepted before reaching build_prompt.
+            // If this branch is hit, the caller has a bug.
+            unreachable!("ContentType::Factual must not reach build_prompt — bypass at worker")
+        }
     };
     parts.push(String::new());
     parts.push(format!("TASK: {}.", task_verb));
@@ -370,6 +397,7 @@ mod tests {
                     TellCategory::Friendly,
                 ],
             }],
+            behavior_modifiers: vec![],
         }
     }
 
@@ -399,6 +427,7 @@ mod tests {
             voice_persona: None,
             voice_examples: vec![],
             occasional_injections: vec![],
+            behavior_modifiers: vec![],
         }
     }