Add test runner registry implementation for v2

This commit introduces a new source file `test_runner_registry.c` that implements the test runner registry for version 2. The file includes definitions for various test runner modules and profiles, along with functions to append sources for different components such as arena, lexer, parser, evaluator, and build model.

Additionally, it defines watch roots for each module to facilitate automatic watching of relevant source files during testing. The new structure enhances the organization and maintainability of the test runner system.

Author: Qfresquin

docs/architecture/code_regions_map.md

@@ -55,7 +55,9 @@ Region responsibilities map to the same product boundary:
 - `src_v2/transpiler/`
 - `src_v2/build_model/`
 - `src_v2/codegen/`
-- `src_v2/build/nob_test.c`
+- `src_v2/build/nob.c`
+- `src_v2/build/nob_testd.c`
+- `src_v2/build/test_runner_*`
 - `test_v2/`
 
 ## Failure Ownership

docs/architecture/pipeline_overview.md

@@ -58,7 +58,10 @@ No layer may bypass the next contract boundary for feature delivery.
 - `src_v2/transpiler/event_ir.*`
 - `src_v2/build_model/*`
 - `src_v2/codegen/*`
-- `test_v2/*` and `src_v2/build/nob_test.c`
+- `src_v2/build/nob.c`
+- `src_v2/build/nob_testd.c`
+- `src_v2/build/test_runner_*`
+- `test_v2/*`
 
 ## Failure Ownership
 

docs/evaluator/evaluator_coverage_matrix.md

@@ -36,7 +36,7 @@ divergences.
 
 ## Differential Program
 
-- Runner: `./build/nob_test test-evaluator-diff`
+- Runner: `./build/nob test evaluator-diff`
 - CMake resolution: `CMK2NOB_TEST_CMAKE_BIN`, then `PATH`
 - Version gate: only `cmake 3.28.x` participates; otherwise the suite skips
 - Optional report output: `NOB_DIFF_STATUS_OUT=/abs/path/report.md`
@@ -58,7 +58,7 @@ divergences.
 - Harness details, DSL, snapshot format, and failure artifacts live in
   [test_v2/evaluator_diff/README.md](../../test_v2/evaluator_diff/README.md)
 - Dedicated CI coverage lives in `.github/workflows/evaluator-diff.yml` and
-  stays separate from the default `test-v2` smoke aggregate
+  stays separate from the default smoke aggregate
 
 ## Audit Matrix
 

docs/tests/README.md

@@ -5,19 +5,13 @@
 This directory is the canonical map for test architecture, suite ownership,
 and active test-infrastructure roadmaps.
 
-Current baseline architecture boundary:
-
-`nob_test runner -> test framework -> shared support -> suites`
-
-Active daemon-program target boundary:
-
 `nob front door -> daemon client/supervisor -> reactor daemon -> runner core -> suites`
 
 ## Overview
 
 The test stack separates:
 
-- aggregate-safe suites (`test-v2`) used as the default smoke baseline
+- aggregate-safe suites used as the default smoke baseline
 - explicit-only host-sensitive suites used for heavy parity/closure proof
 
 This documentation defines test ownership and execution policy. It does not
@@ -35,26 +29,51 @@ redefine evaluator, Event IR, build-model, or codegen product contracts.
 
 ## Execution Policy Summary
 
-Current baseline commands still run through `./build/nob_test` today:
+Current supported human-facing baseline commands now run through `./build/nob test`:
 
 - default smoke aggregate:
-  `./build/nob_test test-v2`
+  `./build/nob test`
+  `./build/nob test smoke`
+- front-doored utility commands:
+  `./build/nob test clean`
+  `./build/nob test tidy all`
+  `./build/nob test tidy <module>`
+- watch mode:
+  `./build/nob test watch <module>`
+  `./build/nob test watch auto`
+- daemon lifecycle:
+  `./build/nob test daemon start`
+  `./build/nob test daemon stop`
+  `./build/nob test daemon status`
 - explicit artifact parity suite:
-  `./build/nob_test test-artifact-parity`
+  `./build/nob test artifact-parity`
 - explicit closure harness suite:
-  `./build/nob_test test-evaluator-codegen-diff`
+  `./build/nob test evaluator-codegen-diff`
 
-The active daemon roadmap treats those commands as transitional and targets:
+The active daemon roadmap now lands its T6 surface on:
 
-- `./build/nob test test-v2`
-- `./build/nob test artifact-parity`
-- `./build/nob test evaluator-codegen-diff`
+- `./build/nob test`
+- `./build/nob test smoke`
+- `./build/nob test clean`
+- `./build/nob test tidy all`
+- `./build/nob test tidy <module>`
 - `./build/nob test watch <module>`
+- `./build/nob test watch auto`
 - `./build/nob test daemon start|stop|status`
+- `./build/nob test artifact-parity`
+- `./build/nob test evaluator-codegen-diff`
+- daemon front-door profile flags:
+  `--verbose`, `--asan`, `--ubsan`, `--msan`, `--san`, `--cov`
 
 That daemon target is intentionally Linux-first and now freezes watch routing,
-cancellation, and fast local feedback as part of the same program, not as
-separate later add-ons.
+cancellation, fast local feedback, and compact failure-first watch ergonomics
+as part of the same program, not as separate later add-ons.
+
+Current T6 limitation:
+- watch sessions are foreground and attached to the active client; there is no
+  persistent detached watch session surface yet.
+- default watch mode is compact and failure-first; use `--verbose` to print
+  roots, full routed path/module sets, and per-rerun fast-path detail.
 
 `artifact-parity` and `evaluator-codegen-diff` remain outside default smoke
 while they stay heavier and host-sensitive.

docs/tests/evaluator_codegen_diff.md

@@ -6,7 +6,7 @@ As of April 6, 2026, `test-evaluator-codegen-diff` is the canonical
 explicit-only closure harness for the remaining
 `evaluator -> Event IR -> build_model -> codegen` gap.
 
-It is intentionally heavier than `test-v2`, remains outside the default smoke
+It is intentionally heavier than the default smoke aggregate, remains outside the default smoke
 aggregate, and is organized around explicit multi-wave closure work rather than
 one undifferentiated backend backlog.
 
@@ -200,18 +200,12 @@ Reasons:
   not the default smoke tier
 
 It therefore does not participate in the current baseline
-`./build/nob_test test-v2` smoke aggregate.
-
-Today the suite is exposed through:
-
-`./build/nob_test test-evaluator-codegen-diff`
-
-The active daemon roadmap treats that command as transitional and targets:
+`./build/nob test` / `./build/nob test smoke` smoke aggregate.
 
 `./build/nob test evaluator-codegen-diff`
 
 Like the other explicit-only host suites, it inherits runner-owned workspace,
-locking, logging, and tool-resolution behavior from `src_v2/build/nob_test.c`.
+locking, logging, and tool-resolution behavior from `src_v2/build/test_runner_*`.
 
 ## Reporting
 

docs/tests/test_daemon_roadmap.md

@@ -5,27 +5,35 @@ rewrite whose sole goal is to reach a fast persistent test daemon as quickly
 as possible.
 
 This document supersedes the old preserved-entrypoint constraint around
-`./build/nob_test` for this program. The current baseline runner still exists
-today, but this roadmap explicitly authorizes replacing it with a new
-`./build/nob`-owned client/daemon architecture even if that breaks the old
-test command surface between waves.
+`./build/nob_test` for this program. The legacy shim is now gone; this roadmap
+explicitly authorized replacing it with a new `./build/nob`-owned
+client/daemon architecture even when that broke the old test command surface
+between waves.
 
 This roadmap does not redefine evaluator, Event IR, build-model, codegen, or
 `nobify` product contracts. It only defines how local and CI-facing test
 infrastructure should evolve to maximize development speed.
 
-## 1. Status
+Historical wave descriptions are preserved below for implementation history.
+Any remaining mentions of `./build/nob_test` or `src_v2/build/nob_test.c`
+inside those earlier-wave sections are historical only, not current guidance.
 
-As of April 8, 2026:
+## 1. Status
 
-- the current baseline test entrypoint is still `./build/nob_test`
-- `src_v2/build/nob.c` does not yet own test dispatch
-- `src_v2/build/nob_test.c` still owns module selection, profiles, incremental
-  compilation, workspaces, logs, and preflight behavior
-- the project now wants a faster path to a persistent daemon than the old
-  compatibility-first test architecture allowed
+As of April 9, 2026:
+
+- `./build/nob test ...` is the official human-facing test entrypoint
+- `build/nob_testd` already owns the daemon-backed run path
+- watch mode and impact routing already exist behind `./build/nob test watch ...`
+- fast profile, daemon-side preflight caching, launcher detection, and parallel
+  object compilation have already landed
+- T5 throughput observability and compact watch ergonomics have already landed
+- T6 legacy surface removal has already landed:
+  - `build/nob_test` has been removed
+  - `clean` and `tidy` are fronted through `./build/nob test ...`
+  - `smoke` is the only supported public aggregate label
 - only the `nobify` product needs portability; test infrastructure does not
-- inter-wave breakage is acceptable if it shortens the path to the daemon
+- inter-wave breakage remains acceptable if it shortens time-to-daemon
 
 The target end state of this roadmap is:
 
@@ -64,12 +72,13 @@ The following decisions are frozen for this roadmap:
 
 - only `nobify` product portability matters
 - test infrastructure may stay Linux/POSIX-only indefinitely
-- `./build/nob_test` is transitional and may be removed later
+- `./build/nob_test` has been removed; any remaining mentions below are
+  historical wave context only
 - `./build/nob` becomes the official human entrypoint for tests
 - `src_v2/build/nob.c` adopts `NOB_GO_REBUILD_URSELF_PLUS(...)` and owns test
   dispatch
-- `src_v2/build/nob_test.c` may remain temporarily, but only as a wrapper or
-  compatibility shim once runner-core extraction begins
+- `src_v2/build/nob_test.c` has been deleted; earlier wave text may still
+  mention it as historical context
 - the new daemon binary is `build/nob_testd`
 - the transport is a pathname `AF_UNIX` socket under `Temp_tests/daemon/`
 - the socket type is `SOCK_SEQPACKET`, not `SOCK_STREAM`
@@ -169,6 +178,10 @@ as a contract that must survive intact.
 
 ## 6. Wave Plan
 
+The wave descriptions below intentionally preserve the state and assumptions
+that were true when each wave was defined. T6 completion supersedes any older
+wave text that still refers to `./build/nob_test` as if it were current.
+
 ### T0 Contract Reset And Program Start
 
 Goal:
@@ -318,6 +331,8 @@ Deliverables:
 - better invalidation/reporting for fast-profile cache hits versus misses
 - explicit fallback routing policy remains visible in watch output when a path
   is unknown or too broad
+- default watch output becomes compact/failure-first, with `--verbose` as the
+  inspection path for roots, routed sets, and per-rerun detail
 
 Non-goals:
 - no full include-graph intelligence
@@ -334,7 +349,7 @@ Goal:
 - remove transitional clutter once the daemon path is stable
 
 Deliverables:
-- `build/nob_test` removed or replaced by a tiny documented compatibility shim
+- `build/nob_test` removed
 - docs stop presenting `./build/nob_test` as primary
 - architecture docs describe `nob` as client/supervisor and `nob_testd` as the
   reactor execution owner