docs(P01): complete minimal-voice-loop phase

---ci---
phase: 1
milestone: v0.1
status: complete
requirements:
  covered: [REQ-VOICE-01, REQ-VOICE-02, REQ-VOICE-03, REQ-VOICE-04, REQ-SCEN-01, REQ-STATE-01, REQ-LLM-01, REQ-LLM-02, REQ-DEBRIEF-01, REQ-ORCH-01, REQ-ORCH-02, REQ-SCEN-FMT-01, REQ-NFR-LAT-01, REQ-NFR-SAFE-01, REQ-NFR-COST-01]
  partial: []
---/ci---

db/migrations/0001_init.sql

@@ -0,0 +1,46 @@
+-- Migration 0001 — initial schema for v0.1 learner state (D-007).
+-- Creates learner, sessions, turns, progress tables + the hardcoded learner-1 row.
+
+-- Schema (also in db/schema.sql for reference; this is the migration source).
+CREATE TABLE IF NOT EXISTS learner (
+    id           TEXT PRIMARY KEY,
+    display_name TEXT NOT NULL,
+    created_at   TEXT NOT NULL DEFAULT (datetime('now'))
+);
+
+CREATE TABLE IF NOT EXISTS sessions (
+    id                    TEXT PRIMARY KEY,
+    learner_id            TEXT NOT NULL REFERENCES learner(id),
+    scenario_id           TEXT NOT NULL,
+    started_at            TEXT NOT NULL DEFAULT (datetime('now')),
+    ended_at              TEXT,
+    branch_path_json      TEXT,
+    outcome               TEXT,
+    cost_estimated_cents  INTEGER,
+    debrief_text          TEXT,
+    cost_breakdown_json   TEXT
+);
+
+CREATE TABLE IF NOT EXISTS turns (
+    id          INTEGER PRIMARY KEY AUTOINCREMENT,
+    session_id  TEXT NOT NULL REFERENCES sessions(id),
+    seq         INTEGER NOT NULL,
+    role        TEXT NOT NULL,
+    asr_text    TEXT,
+    tts_text    TEXT,
+    latency_ms  REAL,
+    created_at  TEXT NOT NULL DEFAULT (datetime('now')),
+    UNIQUE(session_id, seq)
+);
+
+CREATE TABLE IF NOT EXISTS progress (
+    learner_id     TEXT NOT NULL REFERENCES learner(id),
+    scenario_id    TEXT NOT NULL,
+    attempts       INTEGER NOT NULL DEFAULT 0,
+    last_outcome   TEXT,
+    updated_at     TEXT NOT NULL DEFAULT (datetime('now')),
+    PRIMARY KEY (learner_id, scenario_id)
+);
+
+-- The single hardcoded learner row (D-007 — no auth in v0.1).
+INSERT OR IGNORE INTO learner (id, display_name) VALUES ('learner-1', 'Alex');