teacher-prose-only extraction view: coverage, fingerprints, tokens, and batches derive from the teacher's text blocks alone (owner 2026-09-28)

docs/architecture.md

@@ -330,7 +330,7 @@ Sub-agents **verify, never one-shot**: the demo-builder headlessly executes its
 flowchart TB
     TRIG["trigger seam (turn-service): coverageOf(record, coverageLedger)<br/>— uncovered tokens ≥ graph.extractionChunkTokens (settings)?"] -->|"yes, single-flight per source"| RUN["extraction.runExtraction(chatId)"]
     IMPORT["POST /api/graph/import (notes front door)<br/>deterministic src id = sha256(path) — idempotent re-imports"] -->|"importNotes: shared pipeline, second extractor prompt"| RUN
-    RUN --> BATCH["batchRuns — greedy token-budgeted batches of oldest uncovered messages"]
+    RUN --> BATCH["batchRuns — greedy token-budgeted batches of oldest uncovered TEACHER-PROSE messages"]
     BATCH --> EXT["EXTRACTOR (LLM) — sees ONLY the session markdown view<br/>(tree-blind, graph-blind; shared engine: core/session-markdown.ts)"]
     EXT --> AUD["AUDITOR (LLM, agentic loop) — sees findings ONLY, never the source;<br/>explores the graph via find / list_sessions / list_propositions tools,<br/>judges identity (link-or-create, equivalence bias) + may draw bridging edges"]
     AUD --> MERGE["MERGER (deterministic, core/graph.ts) — the ONLY ledger writer:<br/>identity via validated linkTo · bridging-edge resolution · dedupe edges · coverage checkpoint"]
@@ -338,7 +338,7 @@ flowchart TB
     MERGE -->|"failure at ANY stage"| NOTHING["checkpoints nothing — the next trigger re-runs"]
 ```
 
-**Raw reasoning chains only** (2026-09-27 cleanup): the extractor reads ONLY the session — the whole thing, rendered as readable markdown by the shared engine (`core/session-markdown.ts`; the same renderer will serve future user-facing session export) — and proposes free-form propositions (true statements; a misconception is stated as its true correction) and `follows`/`supports` edges. The submit schemas are slim (owner, 2026-09-28): propositions carry id/name/statement/optional aliases and edges carry from/to/type — the `messages` and `evidence` fields are gone (provenance is chat-level; quote fields were never persisted and weak models burned retries on them), and a `prepareArguments` heal at the pre-validation seam rescues stringified-payload submits. Every node is an objective, world-facing fact. No quiz outcomes, no understanding assessments — the events ledger and `UnderstandingLevel` are deleted; the learner's relationship to a proposition becomes practice-module territory (assessment records, later).
+**Raw reasoning chains only** (2026-09-27 cleanup; teacher-prose view 2026-09-28): the extractor reads ONLY the session — and since the 2026-09-28 ruling, ONLY the teacher agent's prose: plain paragraphs under the session title, no learner messages, no thinking, no tool calls or results, no quiz blocks. Coverage fingerprints, slot tokens, and batch budgets all derive from that same selection (`messageViewLines` in `core/coverage.ts`), so "covered" is exactly "what the extractor saw" — a quiz answer or learner edit can never open a run, and only a teacher-prose edit re-opens its message. The old call+result inseparability bond is deleted (nothing left to keep together); batching is pure greedy fill. The shared markdown engine (`core/session-markdown.ts`) keeps the full session format for the future user-facing export and is no longer used by extraction. The extractor proposes free-form propositions (true statements; a misconception is stated as its true correction) and `follows`/`supports` edges. The submit schemas are slim (owner, 2026-09-28): propositions carry id/name/statement/optional aliases and edges carry from/to/type — the `messages` and `evidence` fields are gone (provenance is chat-level; quote fields were never persisted and weak models burned retries on them), and a `prepareArguments` heal at the pre-validation seam rescues stringified-payload submits. Every node is an objective, world-facing fact. No quiz outcomes, no understanding assessments — the events ledger and `UnderstandingLevel` are deleted; the learner's relationship to a proposition becomes practice-module territory (assessment records, later).
 
 **Serialized audit** (owner ruling 2026-09-28): extraction may run in parallel across sources, but the audit→merge section is a process-wide critical section — a FIFO mutex on `globalThis` (the same module-instance idiom as the run registries). Before any auditor LLM call or graph read, a run checks the gate and waits (`waiting` phase, visible in the status feed) until every earlier run's merge has landed, so each auditor explores the graph as it actually stands — two concurrent audits would each link into a graph the other is about to change, the structural mint of duplicate nodes. The lock is reacquired per batch (interleaved runs each see the latest graph instead of starving) and is abort-aware on both sides of the queue.