Implement Meeting Context V1 and extraction improvements

Introduce Meeting Context V1 with YAML schema, validation and template.
Support optional --meeting-context during chunk extraction.
Inject authoritative Meeting Context into extraction prompts.
Record Meeting Context provenance in extraction output.
Activate todos.md in shared prompt assembly.
Strengthen responsibility attribution and decision/todo boundaries.
Add focused Gold scenarios and validation tests.
Update architecture and pipeline documentation.

PROJECT_KNOWLEDGE.md

@@ -23,9 +23,13 @@ Implemented:
   `src/meeting_lab/consolidation/consolidate_facts.py` for facts-only
   semantic duplicate detection.
 - Prompt loading from `src/meeting_lab/llm/prompts.py`.
+- Meeting Context V1 loading, validation and optional extraction prompt
+  injection with minimal extraction JSON provenance.
 - Interim Markdown protocol generation in `src/meeting_lab/protocol/`.
 - Non-LLM unit tests for chunking, extraction helpers, protocol rendering and
   gold-test runner validation.
+- Meeting Context V1 scaffold and documentation for manually maintained
+  meeting metadata.
 
 Experimental/prototype:
 
@@ -38,6 +42,8 @@ Planned:
 - Broader semantic consolidation for topic grouping, contradiction handling,
   uncertainty marking and durable/transient separation.
 - Canonical Meeting Knowledge implementation as the semantic source of truth.
+- Meeting Context integration with Canonicalizer, Semantic Consolidator,
+  Canonical Meeting Knowledge and output renderers.
 - Final Working Protocol / Arbeitsprotokoll, Distribution Protocol /
   Verteilerprotokoll and Knowledge Objects / Wissensdatenbankeintrag renderers.
 
@@ -59,8 +65,10 @@ src/meeting_lab/
 Supporting areas:
 
 - `docs/`: architecture, pipeline, data models and output-view concepts.
-- `prompts/`: active prompt files. Only `common.md` and `decisions.md` contain
-  substantive extraction prompt text in the current tree.
+- `docs/meeting-context.md`: Meeting Context V1 scaffold, fields and future
+  integration rules.
+- `prompts/`: active extraction prompt files. The shared extraction prompt is
+  assembled from `common.md`, `decisions.md` and `todos.md`.
 - `tests/gold/`: semantic gold tests and prompt-engineering methodology.
 - `samples/`: sample inputs and generated or experimental artifacts.
 - `scripts/`: operational scripts for cleanup and gold-test execution.
@@ -111,6 +119,13 @@ Accepted decision semantics:
 - A process decision to defer a substantive decision is still a decision.
 - "No decision was reached" is different from "the group decided to defer the
   decision."
+- A personal commitment to perform concrete future work is normally a todo,
+  not a decision, unless the group also establishes a separate binding outcome,
+  rule, approval, rejection, deferral, selection, process state or
+  responsibility policy.
+- The same proposition should not be duplicated under decisions and todos.
+  Extract both only when the transcript contains a group-level decision and a
+  semantically separate resulting action item.
 
 ## Responsibility Attribution
 
@@ -118,6 +133,13 @@ Meeting Lab distinguishes mentioned people, speakers, participants,
 responsible people, departments, owners and assignees. These concepts must not
 be collapsed into one field.
 
+Meeting Context V1 reinforces this distinction by separating actual
+participants from mentioned non-participants and by storing aliases, roles and
+departments only when they are explicitly supplied as metadata. It must not be
+used to infer responsibilities. In the current implementation this context can
+be injected into chunk extraction prompts as authoritative metadata, and only
+minimal provenance is written to extraction JSON.
+
 A `responsible` or future `owner` / `assignee` value may be recorded only when
 source evidence explicitly assigns, accepts or confirms responsibility. If the
 evidence is incomplete or ambiguous, the responsible person remains `null` or
@@ -125,6 +147,16 @@ unset and the evidence is preserved. Future schema work may add
 `responsibility_status` values such as `explicit`, `accepted`, `proposed` and
 `unclear`, plus `attribution_evidence`.
 
+Meeting Context may validate identity, role, department and attendance, but it
+never establishes responsibility.
+
+Focused Gold coverage now separates these concerns:
+
+- `responsibility_attribution_negative`: tests that discussion, objection and
+  department proximity do not create an owner.
+- `position_explicit_objection`: tests explicit position extraction separately
+  from responsibility attribution.
+
 Current Prompt Version 2 decision baseline:
 
 - `decision_simple`: passing.
@@ -208,10 +240,14 @@ language is requested.
   are the intended architecture.
 - Semantic Consolidator V0 is implemented only for facts-only duplicate
   detection.
+- Meeting Context V1 is implemented only through chunk extraction; later-stage
+  integration remains planned.
 - Canonical Meeting Knowledge is documented but not implemented.
 - Final output views are documented but not implemented.
-- Most prompt files are placeholders except the common and decision prompts.
-- Gold tests currently emphasize extraction semantics, especially decisions.
+- Some prompt files remain placeholders; `common.md`, `decisions.md` and
+  `todos.md` are active in the shared extraction prompt.
+- Gold tests currently emphasize extraction semantics, especially decisions,
+  todos, responsibility attribution and focused position extraction.
 
 ## Next Recommended Engineering Step