Constant CPU_DDL 

pub const CPU_DDL: &str = "
CREATE TABLE IF NOT EXISTS samples (
    id              INTEGER PRIMARY KEY,
    session_id      TEXT NOT NULL REFERENCES sessions(id),
    symbol_id       INTEGER REFERENCES symbols(id),
    thread          TEXT,
    start_us        REAL,
    duration_us     REAL,
    cpu_ns          INTEGER,
    weight          REAL NOT NULL DEFAULT 1.0,
    stack_json      TEXT,
    layer_id        INTEGER REFERENCES layers(id)
);
CREATE INDEX IF NOT EXISTS idx_samples_sym   ON samples(session_id, symbol_id);
CREATE INDEX IF NOT EXISTS idx_samples_start ON samples(session_id, start_us);

CREATE TABLE IF NOT EXISTS counters (
    id              INTEGER PRIMARY KEY,
    session_id      TEXT NOT NULL REFERENCES sessions(id),
    name            TEXT NOT NULL,
    symbol_id       INTEGER REFERENCES symbols(id),
    value           REAL NOT NULL,
    unit            TEXT,
    layer_id        INTEGER REFERENCES layers(id)
);
CREATE INDEX IF NOT EXISTS idx_counters_name ON counters(session_id, name);
";

CPU-unified profile tables — sampling + EAV counters. Used by native-cpu, managed-dotnet, jvm, python, js/node target classes.