conductor(tracks): backfill mcp_architecture_refactor SHA in registry

conductor/tracks.md

@@ -173,7 +173,7 @@ User review surfaced five outstanding UI issues, each previously attempted witho
    *Link: [./tracks/data_structure_strengthening_20260606/](./tracks/data_structure_strengthening_20260606/), Spec: [./tracks/data_structure_strengthening_20260606/spec.md](./tracks/data_structure_strengthening_20260606/spec.md), Plan: [./tracks/data_structure_strengthening_20260606/plan.md](./tracks/data_structure_strengthening_20260606/plan.md) (to be authored by writing-plans skill)*
    *Goal: Improve AI-readability by naming 430 currently-anonymous `dict[str, Any]` / `list[dict[...]]` / `Tuple[...]` types. New `src/type_aliases.py` with 10 `TypeAlias` definitions (`Metadata`, `CommsLogEntry`, `CommsLog`, `HistoryMessage`, `History`, `FileItem`, `FileItems`, `ToolDefinition`, `ToolCall`, `CommsLogCallback`) and 1 `NamedTuple` (`FileItemsDiff`). Mechanical replacement of 345 weak sites across 6 high-traffic files: `src/ai_client.py` (139), `src/app_controller.py` (86), `src/models.py` (51), `src/api_hook_client.py` (32), `src/project_manager.py` (20), `src/aggregate.py` (17). Add `--strict` mode to the existing `scripts/audit_weak_types.py` (committed in 84fd9ac9; found the 430 sites) so it becomes a permanent CI gate that fails when new weak types are introduced. Generate `scripts/audit_weak_types.baseline.json` with the post-refactor count. 2 phases: aliases + 6-file replacement + audit baseline; NamedTuples + docs + archive. **Data-grounded**: the audit script is the source of truth; the count drops from 430 to ~60 (86% reduction) in the 6 high-traffic files. **Honest about what's missing**: 23 lower-impact files remain; TypedDict/dataclass migration is deferred to a follow-up track. 2-3 days work, 1-2 phases, low risk.*
 
-0g. [ ] **Track: MCP Architecture Refactor (Sub-MCP Extraction)** `[track-created: <pending>]`
+0g. [ ] **Track: MCP Architecture Refactor (Sub-MCP Extraction)** `[track-created: 2720a894]`
    *Link: [./tracks/mcp_architecture_refactor_20260606/](./tracks/mcp_architecture_refactor_20260606/), Spec: [./tracks/mcp_architecture_refactor_20260606/spec.md](./tracks/mcp_architecture_refactor_20260606/spec.md), Plan: [./tracks/mcp_architecture_refactor_20260606/plan.md](./tracks/mcp_architecture_refactor_20260606/plan.md) (to be authored by writing-plans skill)*
    *Goal: Split the 2,205-line monolithic `src/mcp_client.py` (45 module-level functions) into a slim controller + 6 native sub-MCPs + 1 external sub-MCP. Naming convention `mcp_<type>.py` for native MCPs: `mcp_file_io.py` (9 tools), `mcp_python.py` (14), `mcp_c.py` (5), `mcp_cpp.py` (5), `mcp_web.py` (2), `mcp_analysis.py` (2). The existing `ExternalMCPManager` is extracted to `mcp_external.py` (class name preserved). New `MCPController` class in `src/mcp_client.py` holds the 3-layer security model (extracted to `src/mcp_client_security.py`), the `ALL_SUB_MCPS` registration list, and the inverted-dict dispatch lookup. New `src/mcp_client_legacy.py` re-exports all 45+ old symbols for backward compat (the 4 existing test files + `src/app_controller.py:61` continue to work). Each sub-MCP's `invoke()` returns `Result[str, ErrorInfo]` (Fleury pattern). Path parameters use the `Metadata` family aliases. **Blocked by** `data_oriented_error_handling_20260606` (for `Result`/`ErrorInfo`) and `data_structure_strengthening_20260606` (for `Metadata` aliases). 7 phases: foundation (security + controller), move-to-legacy, extract File I/O, extract Python, extract C/C++/Web/Analysis, extract External, dispatch update + docs + archive. **Out of scope** (per user): a per-MCP DSL (APL/K/Cosy-inspired) for compact tool calls — deferred to `mcp_dsl_20260606` follow-up. JSON-only for now.*