conductor(plan): mark Phase 0 complete (setup + styleguide re-read)

TIER-2 READ conductor/code_styleguides/error_handling.md end-to-end before Phase 0.

Phase 0 covered:
- t0.1 [bf94fb2]: Update conductor/tracks.md (ready to start -> active 2026-06-19)
- t0.2 [62188d6]: Styleguide re-read (empty commit acknowledging AI Agent Checklist Rule #0)
- t0.3 [this commit]: Phase 0 checkpoint; state.toml Phase 0 status -> completed

Phase 0 establishes the anti-sliming protocol for the 42 migration-target sites
in src/gui_2.py. Each subsequent phase starts with a styleguide re-read + ack
in the commit message (Rule #0 enforcement).

conductor/tracks/result_migration_gui_2_20260619/plan.md

@@ -56,16 +56,16 @@ The previous sub-tracks slimed when scope felt tight (sub-track 2 Phase 10 slime
 
 **Focus:** Initialize the track, update tracks.md, Tier 2 reads the styleguide end-to-end, acknowledge in commit message.
 
-### Task 0.1: Update `conductor/tracks.md`
+### Task 0.1: Update `conductor/tracks.md` [bf94fb2]
 
 **Files:**
 - Modify: `conductor/tracks.md` (add new row in the "Active Tracks (Current Queue)" table, after row 6d-3)
 
-- [ ] **Step 1: Read the current tracks.md row for sub-track 3**
+- [x] **Step 1: Read the current tracks.md row for sub-track 3**
 
 Run: `grep -n "result_migration_app_controller_20260618" conductor/tracks.md | head -5`
 
-- [ ] **Step 2: Add the new row after sub-track 3**
+- [x] **Step 2: Add the new row after sub-track 3**
 
 Insert in the "Active Tracks (Current Queue)" table (between row 6d-3 and row 6e):
 
@@ -73,18 +73,18 @@ Insert in the "Active Tracks (Current Queue)" table (between row 6d-3 and row 6e
 | 6d-4 | A | [Result Migration Sub-Track 4: gui_2.py](#track-result-migration-sub-track-4-gui_2py-20260619) | spec ✓, plan pending, **ready to start** | `result_migration_app_controller_20260618` (sub-track 3, SHIPPED 2026-06-19 with Phase 7) |
 ```
 
-- [ ] **Step 3: Commit**
+- [x] **Step 3: Commit**
 
 ```bash
 git add conductor/tracks.md
 git commit -m "conductor(tracks): add result_migration_gui_2_20260619 row"
 ```
 
-### Task 0.2: Tier 2 reads the styleguide end-to-end
+### Task 0.2: Tier 2 reads the styleguide end-to-end [62188d6]
 
 **Files:** (no file changes; verification is the commit message)
 
-- [ ] **Step 1: Read `conductor/code_styleguides/error_handling.md` end-to-end**
+- [x] **Step 1: Read `conductor/code_styleguides/error_handling.md` end-to-end**
 
 This file is 989 lines. Read all sections:
 1. The 5 Patterns (lines 22-130)
@@ -111,7 +111,7 @@ git commit --allow-empty -m "chore: TIER-2 READ conductor/code_styleguides/error
 
 ### Task 0.3: Phase 0 checkpoint
 
-- [ ] **Step 1: Create empty commit marking Phase 0 complete**
+- [x] **Step 1: Create empty commit marking Phase 0 complete**
 
 ```bash
 git commit --allow-empty -m "conductor(plan): mark Phase 0 complete (setup + styleguide re-read)"

conductor/tracks/result_migration_gui_2_20260619/state.toml

@@ -18,7 +18,7 @@ result_migration_app_controller_20260618 = "shipped 2026-06-19 (with Phase 7); d
 result_migration_baseline_cleanup = "blocked by this track; date TBD when this track ships"
 
 [phases]
-phase_0 = { status = "pending", checkpointsha = "", name = "Setup + styleguide re-read (3 tasks)" }
+phase_0 = { status = "completed", checkpointsha = "62188d6", name = "Setup + styleguide re-read (3 tasks)" }
 phase_1 = { status = "pending", checkpointsha = "", name = "Site inventory + classification (3 tasks; 42 sites in PHASE1_SITE_INVENTORY.md)" }
 phase_2 = { status = "pending", checkpointsha = "", name = "Drain plane wiring (4 tasks; 3 new render functions + 2 invariant tests)" }
 phase_3 = { status = "pending", checkpointsha = "", name = "INTERNAL_BROAD_CATCH Batch A — render-loop sites (<=10 sites)" }
@@ -35,9 +35,9 @@ phase_13 = { status = "pending", checkpointsha = "", name = "Audit gate + end-of
 
 [tasks]
 # Phase 0: Setup + styleguide re-read (3 tasks)
-t0_1 = { status = "pending", commit_sha = "", description = "Update conductor/tracks.md with the new track row" }
-t0_2 = { status = "pending", commit_sha = "", description = "Tier 2 reads conductor/code_styleguides/error_handling.md end-to-end; acknowledge in commit message" }
-t0_3 = { status = "pending", commit_sha = "", description = "Phase 0 checkpoint commit; update state.toml Phase 0 status" }
+t0_1 = { status = "completed", commit_sha = "bf94fb2", description = "Update conductor/tracks.md with the new track row" }
+t0_2 = { status = "completed", commit_sha = "62188d6", description = "Tier 2 reads conductor/code_styleguides/error_handling.md end-to-end; acknowledge in commit message" }
+t0_3 = { status = "in_progress", commit_sha = "", description = "Phase 0 checkpoint commit; update state.toml Phase 0 status" }
 
 # Phase 1: Site inventory + classification (3 tasks)
 t1_1 = { status = "pending", commit_sha = "", description = "Run audit --src src/gui_2.py --json > tests/artifacts/PHASE1_AUDIT.json" }
@@ -165,7 +165,7 @@ t13_4 = { status = "pending", commit_sha = "", description = "Write docs/reports
 t13_5 = { status = "pending", commit_sha = "", description = "Final checkpoint + tracks.md update + umbrella count update" }
 
 [verification]
-phase_0_complete = false
+phase_0_complete = true
 phase_1_complete = false
 phase_2_complete = false
 phase_3_complete = false